+@c -*-texinfo-*-
+@c This is part of the GNU Guile Reference Manual.
+@c Copyright (C) 1996, 1997, 2000, 2001, 2002, 2003, 2004
+@c Free Software Foundation, Inc.
+@c See the file guile.texi for copying conditions.
+
@node POSIX
-@chapter POSIX System Calls and Networking
+@section @acronym{POSIX} System Calls and Networking
+@cindex POSIX
@menu
* Conventions:: Conventions employed by the POSIX interface.
@end menu
@node Conventions
-@section POSIX Interface Conventions
+@subsection @acronym{POSIX} Interface Conventions
These interfaces provide access to operating system facilities.
They provide a simple wrapping around the underlying C interfaces
to make usage from Scheme more convenient. They are also used
-to implement the Guile port of @ref{The Scheme shell (scsh)}.
+to implement the Guile port of scsh (@pxref{The Scheme shell (scsh)}).
Generally there is a single procedure for each corresponding Unix
facility. There are some exceptions, such as procedures implemented for
speed and convenience in Scheme with no primitive Unix equivalent,
-e.g., @code{copy-file}.
+e.g.@: @code{copy-file}.
The interfaces are intended as far as possible to be portable across
different versions of Unix. In some cases procedures which can't be
string is not found in the environment. These cases are noted in
the documentation.
-For ways to deal with exceptions, @ref{Exceptions}.
+For ways to deal with exceptions, see @ref{Exceptions}.
-Errors which the C-library would report by returning a NULL pointer or
+@cindex @code{errno}
+Errors which the C library would report by returning a null pointer or
through some other means are reported by raising a @code{system-error}
-exception. The value of the Unix @code{errno} variable is available
-in the data passed by the exception.
+exception with @code{scm-error} (@pxref{Error Reporting}). The
+@var{data} parameter is a list containing the Unix @code{errno} value
+(an integer). For example,
+
+@example
+(define (my-handler key func fmt fmtargs data)
+ (display key) (newline)
+ (display func) (newline)
+ (apply format #t fmt fmtargs) (newline)
+ (display data) (newline))
+
+(catch 'system-error
+ (lambda () (dup2 -123 -456))
+ my-handler)
+
+@print{}
+system-error
+dup2
+Bad file descriptor
+(9)
+@end example
+
-It can be extracted with the function @code{system-error-errno}:
+@sp 1
+@defun system-error-errno arglist
+@cindex @code{errno}
+Return the @code{errno} value from a list which is the arguments to an
+exception handler. If the exception is not a @code{system-error},
+then the return is @code{#f}. For example,
@example
(catch
(display (strerror errno))))
(newline))))
@end example
+@end defun
+
@node Ports and File Descriptors
-@section Ports and File Descriptors
+@subsection Ports and File Descriptors
+@cindex file descriptor
Conventions generally follow those of scsh, @ref{The Scheme shell (scsh)}.
File ports are implemented using low-level operating system I/O
-facilities, with optional buffering to improve efficiency
-@pxref{File Ports}
+facilities, with optional buffering to improve efficiency; see
+@ref{File Ports}.
Note that some procedures (e.g., @code{recv!}) will accept ports as
arguments, but will actually operate directly on the file descriptor
side-effect of closing the file descriptor prematurely.
To assist the programmer in avoiding this problem, each port has an
-associated "revealed count" which can be used to keep track of how many
+associated @dfn{revealed count} which can be used to keep track of how many
times the underlying file descriptor has been stored in other places.
If a port's revealed count is greater than zero, the file descriptor
will not be closed when the port is garbage collected. A programmer
can therefore ensure that the revealed count will be greater than
zero if the file descriptor is needed elsewhere.
-For the simple case where a file descriptor is "imported" once to become
+For the simple case where a file descriptor is ``imported'' once to become
a port, it does not matter if the file descriptor is closed when the
port is garbage collected. There is no need to maintain a revealed
-count. Likewise when "exporting" a file descriptor to the external
+count. Likewise when ``exporting'' a file descriptor to the external
environment, setting the revealed count is not required provided the
port is kept open (i.e., is pointed to by a live Scheme binding) while
the file descriptor is in use.
-To correspond with traditional Unix behaviour, the three file
-descriptors (0, 1 and 2) are automatically imported when a program
-starts up and assigned to the initial values of the current input,
-output and error ports. The revealed count for each is initially set to
-one, so that dropping references to one of these ports will not result
-in its garbage collection: it could be retrieved with fdopen or
-fdes->ports.
+To correspond with traditional Unix behaviour, three file descriptors
+(0, 1, and 2) are automatically imported when a program starts up and
+assigned to the initial values of the current/standard input, output,
+and error ports, respectively. The revealed count for each is
+initially set to one, so that dropping references to one of these
+ports will not result in its garbage collection: it could be retrieved
+with @code{fdopen} or @code{fdes->ports}.
@deffn {Scheme Procedure} port-revealed port
@deffnx {C Function} scm_port_revealed (port)
@deffn {Scheme Procedure} set-port-revealed! port rcount
@deffnx {C Function} scm_set_port_revealed_x (port, rcount)
-Sets the revealed count for a port to a given value.
+Sets the revealed count for a @var{port} to @var{rcount}.
The return value is unspecified.
@end deffn
@deffn {Scheme Procedure} fdopen fdes modes
@deffnx {C Function} scm_fdopen (fdes, modes)
-Return a new port based on the file descriptor @var{fdes}.
-Modes are given by the string @var{modes}. The revealed count
-of the port is initialized to zero. The modes string is the
-same as that accepted by @ref{File Ports, open-file}.
+Return a new port based on the file descriptor @var{fdes}. Modes are
+given by the string @var{modes}. The revealed count of the port is
+initialized to zero. The @var{modes} string is the same as that
+accepted by @code{open-file} (@pxref{File Ports, open-file}).
@end deffn
@deffn {Scheme Procedure} fdes->ports fd
@deffnx {C Function} scm_open (path, flags, mode)
Open the file named by @var{path} for reading and/or writing.
@var{flags} is an integer specifying how the file should be opened.
-@var{mode} is an integer specifying the permission bits of the file, if
-it needs to be created, before the umask is applied. The default is 666
-(Unix itself has no default).
+@var{mode} is an integer specifying the permission bits of the file,
+if it needs to be created, before the umask (@pxref{Processes}) is
+applied. The default is 666 (Unix itself has no default).
@var{flags} can be constructed by combining variables using @code{logior}.
Basic flags are:
Create the file if it does not already exist.
@end defvar
-See the Unix documentation of the @code{open} system call
+@xref{File Status Flags,,,libc,The GNU C Library Reference Manual},
for additional flags.
@end deffn
@deffn {Scheme Procedure} close fd_or_port
@deffnx {C Function} scm_close (fd_or_port)
-Similar to close-port (@pxref{Closing, close-port}),
+Similar to @code{close-port} (@pxref{Closing, close-port}),
but also works on file descriptors. A side
effect of closing a file descriptor is that any ports using that file
descriptor are moved to a different file descriptor and have
@deffn {Scheme Procedure} close-fdes fd
@deffnx {C Function} scm_close_fdes (fd)
-A simple wrapper for the @code{close} system call.
-Close file descriptor @var{fd}, which must be an integer.
-Unlike close (@pxref{Ports and File Descriptors, close}),
-the file descriptor will be closed even if a port is using it.
-The return value is unspecified.
+A simple wrapper for the @code{close} system call. Close file
+descriptor @var{fd}, which must be an integer. Unlike @code{close},
+the file descriptor will be closed even if a port is using it. The
+return value is unspecified.
@end deffn
@deffn {Scheme Procedure} unread-char char [port]
@deffnx {C Function} scm_unread_char (char, port)
-Place @var{char} in @var{port} so that it will be read by the
-next read operation. If called multiple times, the unread characters
-will be read again in last-in first-out order. If @var{port} is
-not supplied, the current input port is used.
+Place @var{char} in @var{port} so that it will be read by the next
+read operation on that port. If called multiple times, the unread
+characters will be read again in ``last-in, first-out'' order (i.e.@:
+a stack). If @var{port} is not supplied, the current input port is
+used.
@end deffn
@deffn {Scheme Procedure} unread-string str port
@deffn {Scheme Procedure} pipe
@deffnx {C Function} scm_pipe ()
+@cindex pipe
Return a newly created pipe: a pair of ports which are linked
-together on the local machine. The @emph{car} is the input
-port and the @emph{cdr} is the output port. Data written (and
+together on the local machine. The @acronym{CAR} is the input
+port and the @acronym{CDR} is the output port. Data written (and
flushed) to the output port can be read from the input port.
Pipes are commonly used for communication with a newly forked
child process. The need to flush the output port can be
avoided by making it unbuffered using @code{setvbuf}.
-Writes occur atomically provided the size of the data in bytes
-is not greater than the value of @code{PIPE_BUF}. Note that
-the output port is likely to block if too much data (typically
-equal to @code{PIPE_BUF}) has been written but not yet read
-from the input port.
+@defvar PIPE_BUF
+A write of up to @code{PIPE_BUF} many bytes to a pipe is atomic,
+meaning when done it goes into the pipe instantaneously and as a
+contiguous block (@pxref{Pipe Atomicity,, Atomicity of Pipe I/O, libc,
+The GNU C Library Reference Manual}).
+@end defvar
+
+Note that the output port is likely to block if too much data has been
+written but not yet read from the input port. Typically the capacity
+is @code{PIPE_BUF} bytes.
@end deffn
The next group of procedures perform a @code{dup2}
number @var{newfd}, replacing the previous meaning
of @var{newfd}. Both @var{oldfd} and @var{newfd} must
be integers.
-Unlike for dup->fdes or primitive-move->fdes, no attempt
+Unlike for @code{dup->fdes} or @code{primitive-move->fdes}, no attempt
is made to move away ports which are using @var{newfd}.
The return value is unspecified.
@end deffn
@deffn {Scheme Procedure} port-mode port
Return the port modes associated with the open port @var{port}.
These will not necessarily be identical to the modes used when
-the port was opened, since modes such as "append" which are
+the port was opened, since modes such as ``append'' which are
used only during port creation are not retained.
@end deffn
@deffn {Scheme Procedure} port-for-each proc
-@deffnx {C Function} scm_port_for_each (proc)
+@deffnx {C Function} scm_port_for_each (SCM proc)
+@deffnx {C Function} scm_c_port_for_each (void (*proc)(void *, SCM), void *data)
Apply @var{proc} to each port in the Guile port table
+(FIXME: what is the Guile port table?)
in turn. The return value is unspecified. More specifically,
-@var{proc} is applied exactly once to every port that exists
-in the system at the time @var{port-for-each} is invoked.
-Changes to the port table while @var{port-for-each} is running
-have no effect as far as @var{port-for-each} is concerned.
+@var{proc} is applied exactly once to every port that exists in the
+system at the time @code{port-for-each} is invoked. Changes to the
+port table while @code{port-for-each} is running have no effect as far
+as @code{port-for-each} is concerned.
+
+The C function @code{scm_port_for_each} takes a Scheme procedure
+encoded as a @code{SCM} value, while @code{scm_c_port_for_each} takes
+a pointer to a C function and passes along a arbitrary @var{data}
+cookie.
@end deffn
@deffn {Scheme Procedure} setvbuf port mode [size]
@deffnx {C Function} scm_setvbuf (port, mode, size)
+@cindex port buffering
Set the buffering mode for @var{port}. @var{mode} can be:
-@table @code
-@item _IONBF
+
+@defvar _IONBF
non-buffered
-@item _IOLBF
+@end defvar
+@defvar _IOLBF
line buffered
-@item _IOFBF
+@end defvar
+@defvar _IOFBF
block buffered, using a newly allocated buffer of @var{size} bytes.
If @var{size} is omitted, a default size will be used.
-@end table
+@end defvar
@end deffn
@deffn {Scheme Procedure} fcntl object cmd [value]
Values for @var{command} are:
-@table @code
-@item F_DUPFD
+@defvar F_DUPFD
Duplicate a file descriptor
-@item F_GETFD
+@end defvar
+@defvar F_GETFD
Get flags associated with the file descriptor.
-@item F_SETFD
+@end defvar
+@defvar F_SETFD
Set flags associated with the file descriptor to @var{value}.
-@item F_GETFL
+@end defvar
+@defvar F_GETFL
Get flags associated with the open file.
-@item F_SETFL
+@end defvar
+@defvar F_SETFL
Set flags associated with the open file to @var{value}
-@item F_GETOWN
+@end defvar
+@defvar F_GETOWN
Get the process ID of a socket's owner, for @code{SIGIO} signals.
-@item F_SETOWN
+@end defvar
+@defvar F_SETOWN
Set the process that owns a socket to @var{value}, for @code{SIGIO} signals.
-@item FD_CLOEXEC
-The value used to indicate the "close on exec" flag with @code{F_GETFL} or
+@end defvar
+@defvar FD_CLOEXEC
+The value used to indicate the ``close on exec'' flag with @code{F_GETFL} or
@code{F_SETFL}.
-@end table
+@end defvar
@end deffn
@deffn {Scheme Procedure} flock file operation
@deffnx {C Function} scm_flock (file, operation)
+@cindex file locking
Apply or remove an advisory lock on an open file.
@var{operation} specifies the action to be done:
-@table @code
-@item LOCK_SH
+
+@defvar LOCK_SH
Shared lock. More than one process may hold a shared lock
for a given file at a given time.
-@item LOCK_EX
+@end defvar
+@defvar LOCK_EX
Exclusive lock. Only one process may hold an exclusive lock
for a given file at a given time.
-@item LOCK_UN
+@end defvar
+@defvar LOCK_UN
Unlock the file.
-@item LOCK_NB
+@end defvar
+@defvar LOCK_NB
Don't block when locking. May be specified by bitwise OR'ing
it to one of the other operations.
-@end table
+@end defvar
+
The return value is not specified. @var{file} may be an open
file descriptor or an open file descriptor port.
@end deffn
@end deffn
@node File System
-@section File System
+@subsection File System
+@cindex file system
These procedures allow querying and setting file system attributes
(such as owner,
@deffn {Scheme Procedure} access? path how
@deffnx {C Function} scm_access (path, how)
-Return @code{#t} if @var{path} corresponds to an existing file
-and the current process has the type of access specified by
-@var{how}, otherwise @code{#f}. @var{how} should be specified
-using the values of the variables listed below. Multiple
-values can be combined using a bitwise or, in which case
-@code{#t} will only be returned if all accesses are granted.
+Test accessibility of a file under the real UID and GID of the calling
+process. The return is @code{#t} if @var{path} exists and the
+permissions requested by @var{how} are all allowed, or @code{#f} if
+not.
-Permissions are checked using the real id of the current
-process, not the effective id, although it's the effective id
-which determines whether the access would actually be granted.
+@var{how} is an integer which is one of the following values, or a
+bitwise-OR (@code{logior}) of multiple values.
@defvar R_OK
-test for read permission.
+Test for read permission.
@end defvar
@defvar W_OK
-test for write permission.
+Test for write permission.
@end defvar
@defvar X_OK
-test for execute permission.
+Test for execute permission.
@end defvar
@defvar F_OK
-test for existence of the file.
+Test for existence of the file. This is implied by each of the other
+tests, so there's no need to combine it with them.
@end defvar
+
+It's important to note that @code{access?} does not simply indicate
+what will happen on attempting to read or write a file. In normal
+circumstances it does, but in a set-UID or set-GID program it doesn't
+because @code{access?} tests the real ID, whereas an open or execute
+attempt uses the effective ID.
+
+A program which will never run set-UID/GID can ignore the difference
+between real and effective IDs, but for maximum generality, especially
+in library functions, it's best not to use @code{access?} to predict
+the result of an open or execute, instead simply attempt that and
+catch any exception.
+
+The main use for @code{access?} is to let a set-UID/GID program
+determine what the invoking user would have been allowed to do,
+without the greater (or perhaps lesser) privileges afforded by the
+effective ID. For more on this, see @ref{Testing File Access,,, libc,
+The GNU C Library Reference Manual}.
@end deffn
@findex fstat
parameter to the following procedures, all of which return
integers:
-@table @code
-@item stat:dev
-The device containing the file.
-@item stat:ino
+@deffn {Scheme Procedure} stat:dev st
+The device number containing the file.
+@end deffn
+@deffn {Scheme Procedure} stat:ino st
The file serial number, which distinguishes this file from all
other files on the same device.
-@item stat:mode
-The mode of the file. This includes file type information and
-the file permission bits. See @code{stat:type} and
+@end deffn
+@deffn {Scheme Procedure} stat:mode st
+The mode of the file. This is an integer which incorporates file type
+information and file permission bits. See also @code{stat:type} and
@code{stat:perms} below.
-@item stat:nlink
+@end deffn
+@deffn {Scheme Procedure} stat:nlink st
The number of hard links to the file.
-@item stat:uid
+@end deffn
+@deffn {Scheme Procedure} stat:uid st
The user ID of the file's owner.
-@item stat:gid
+@end deffn
+@deffn {Scheme Procedure} stat:gid st
The group ID of the file.
-@item stat:rdev
-Device ID; this entry is defined only for character or block
-special files.
-@item stat:size
+@end deffn
+@deffn {Scheme Procedure} stat:rdev st
+Device ID; this entry is defined only for character or block special
+files. On some systems this field is not available at all, in which
+case @code{stat:rdev} returns @code{#f}.
+@end deffn
+@deffn {Scheme Procedure} stat:size st
The size of a regular file in bytes.
-@item stat:atime
+@end deffn
+@deffn {Scheme Procedure} stat:atime st
The last access time for the file.
-@item stat:mtime
+@end deffn
+@deffn {Scheme Procedure} stat:mtime st
The last modification time for the file.
-@item stat:ctime
+@end deffn
+@deffn {Scheme Procedure} stat:ctime st
The last modification time for the attributes of the file.
-@item stat:blksize
-The optimal block size for reading or writing the file, in
-bytes.
-@item stat:blocks
-The amount of disk space that the file occupies measured in
-units of 512 byte blocks.
-@end table
+@end deffn
+@deffn {Scheme Procedure} stat:blksize st
+The optimal block size for reading or writing the file, in bytes. On
+some systems this field is not available, in which case
+@code{stat:blksize} returns a sensible suggested block size.
+@end deffn
+@deffn {Scheme Procedure} stat:blocks st
+The amount of disk space that the file occupies measured in units of
+512 byte blocks. On some systems this field is not available, in
+which case @code{stat:blocks} returns @code{#f}.
+@end deffn
In addition, the following procedures return the information
-from stat:mode in a more convenient form:
+from @code{stat:mode} in a more convenient form:
-@table @code
-@item stat:type
+@deffn {Scheme Procedure} stat:type st
A symbol representing the type of file. Possible values are
-regular, directory, symlink, block-special, char-special, fifo,
-socket and unknown
-@item stat:perms
+@samp{regular}, @samp{directory}, @samp{symlink},
+@samp{block-special}, @samp{char-special}, @samp{fifo}, @samp{socket},
+and @samp{unknown}.
+@end deffn
+@deffn {Scheme Procedure} stat:perms st
An integer representing the access permission bits.
-@end table
+@end deffn
@end deffn
@deffn {Scheme Procedure} lstat str
@findex lchown
@deffn {Scheme Procedure} chown object owner group
@deffnx {C Function} scm_chown (object, owner, group)
-Change the ownership and group of the file referred to by @var{object} to
-the integer values @var{owner} and @var{group}. @var{object} can be
-a string containing a file name or, if the platform
-supports fchown, a port or integer file descriptor
-which is open on the file. The return value
-is unspecified.
+Change the ownership and group of the file referred to by @var{object}
+to the integer values @var{owner} and @var{group}. @var{object} can
+be a string containing a file name or, if the platform supports
+@code{fchown} (@pxref{File Owner,,,libc,The GNU C Library Reference
+Manual}), a port or integer file descriptor which is open on the file.
+The return value is unspecified.
If @var{object} is a symbolic link, either the
ownership of the link or the ownership of the referenced file will be
@deffn {Scheme Procedure} utime pathname [actime [modtime]]
@deffnx {C Function} scm_utime (pathname, actime, modtime)
+@cindex file times
@code{utime} sets the access and modification times for the
file named by @var{path}. If @var{actime} or @var{modtime} is
not supplied, then the current time is used. @var{actime} and
@findex unlink
@deffn {Scheme Procedure} delete-file str
@deffnx {C Function} scm_delete_file (str)
-Deletes (or "unlinks") the file specified by @var{path}.
+Deletes (or ``unlinks'') the file whose path is specified by
+@var{str}.
@end deffn
@deffn {Scheme Procedure} copy-file oldfile newfile
@deffnx {C Function} scm_copy_file (oldfile, newfile)
-Copy the file specified by @var{path-from} to @var{path-to}.
+Copy the file specified by @var{oldfile} to @var{newfile}.
The return value is unspecified.
@end deffn
@deffn {Scheme Procedure} symlink oldpath newpath
@deffnx {C Function} scm_symlink (oldpath, newpath)
-Create a symbolic link named @var{path-to} with the value (i.e., pointing to)
-@var{path-from}. The return value is unspecified.
+Create a symbolic link named @var{newpath} with the value (i.e., pointing to)
+@var{oldpath}. The return value is unspecified.
@end deffn
@deffn {Scheme Procedure} mkdir path [mode]
@deffnx {C Function} scm_mkdir (path, mode)
Create a new directory named by @var{path}. If @var{mode} is omitted
then the permissions of the directory file are set using the current
-umask. Otherwise they are set to the decimal value specified with
-@var{mode}. The return value is unspecified.
+umask (@pxref{Processes}). Otherwise they are set to the decimal
+value specified with @var{mode}. The return value is unspecified.
@end deffn
@deffn {Scheme Procedure} rmdir path
@deffn {Scheme Procedure} opendir dirname
@deffnx {C Function} scm_opendir (dirname)
-Open the directory specified by @var{path} and return a directory
+@cindex directory contents
+Open the directory specified by @var{dirname} and return a directory
stream.
@end deffn
-@deffn {Scheme Procedure} directory-stream? obj
-@deffnx {C Function} scm_directory_stream_p (obj)
+@deffn {Scheme Procedure} directory-stream? object
+@deffnx {C Function} scm_directory_stream_p (object)
Return a boolean indicating whether @var{object} is a directory
stream as returned by @code{opendir}.
@end deffn
-@deffn {Scheme Procedure} readdir port
-@deffnx {C Function} scm_readdir (port)
+@deffn {Scheme Procedure} readdir stream
+@deffnx {C Function} scm_readdir (stream)
Return (as a string) the next directory entry from the directory stream
@var{stream}. If there is no remaining entry to be read then the
end of file object is returned.
@end deffn
-@deffn {Scheme Procedure} rewinddir port
-@deffnx {C Function} scm_rewinddir (port)
+@deffn {Scheme Procedure} rewinddir stream
+@deffnx {C Function} scm_rewinddir (stream)
Reset the directory port @var{stream} so that the next call to
@code{readdir} will return the first directory entry.
@end deffn
-@deffn {Scheme Procedure} closedir port
-@deffnx {C Function} scm_closedir (port)
+@deffn {Scheme Procedure} closedir stream
+@deffnx {C Function} scm_closedir (stream)
Close the directory stream @var{stream}.
The return value is unspecified.
@end deffn
@deffn {Scheme Procedure} mknod path type perms dev
@deffnx {C Function} scm_mknod (path, type, perms, dev)
+@cindex device file
Creates a new special file, such as a file corresponding to a device.
-@var{path} specifies the name of the file. @var{type} should
-be one of the following symbols:
-regular, directory, symlink, block-special, char-special,
-fifo, or socket. @var{perms} (an integer) specifies the file permissions.
-@var{dev} (an integer) specifies which device the special file refers
-to. Its exact interpretation depends on the kind of special file
-being created.
+@var{path} specifies the name of the file. @var{type} should be one
+of the following symbols: @samp{regular}, @samp{directory},
+@samp{symlink}, @samp{block-special}, @samp{char-special},
+@samp{fifo}, or @samp{socket}. @var{perms} (an integer) specifies the
+file permissions. @var{dev} (an integer) specifies which device the
+special file refers to. Its exact interpretation depends on the kind
+of special file being created.
E.g.,
@lisp
@deffn {Scheme Procedure} tmpnam
@deffnx {C Function} scm_tmpnam ()
+@cindex temporary file
Return a name in the file system that does not match any
existing file. However there is no guarantee that another
process will not create the file after @code{tmpnam} is called.
@deffn {Scheme Procedure} mkstemp! tmpl
@deffnx {C Function} scm_mkstemp (tmpl)
+@cindex temporary file
Create a new unique file in the file system and returns a new
buffered port open for reading and writing to the file.
+
@var{tmpl} is a string specifying where the file should be
-created: it must end with @code{XXXXXX} and will be changed in
+created: it must end with @samp{XXXXXX} and will be changed in
place to return the name of the temporary file.
+
+The file is created with mode @code{0600}, which means read and write
+for the owner only. @code{chmod} can be used to change this.
@end deffn
@deffn {Scheme Procedure} dirname filename
@node User Information
-@section User Information
+@subsection User Information
+@cindex user information
+@cindex password file
+@cindex group file
The facilities in this section provide an interface to the user and
group database.
The following functions accept an object representing user information
and return a selected component:
-@table @code
-@item passwd:name
+@deffn {Scheme Procedure} passwd:name pw
The name of the userid.
-@item passwd:passwd
+@end deffn
+@deffn {Scheme Procedure} passwd:passwd pw
The encrypted passwd.
-@item passwd:uid
+@end deffn
+@deffn {Scheme Procedure} passwd:uid pw
The user id number.
-@item passwd:gid
+@end deffn
+@deffn {Scheme Procedure} passwd:gid pw
The group id number.
-@item passwd:gecos
+@end deffn
+@deffn {Scheme Procedure} passwd:gecos pw
The full name.
-@item passwd:dir
+@end deffn
+@deffn {Scheme Procedure} passwd:dir pw
The home directory.
-@item passwd:shell
+@end deffn
+@deffn {Scheme Procedure} passwd:shell pw
The login shell.
-@end table
+@end deffn
+@sp 1
@deffn {Scheme Procedure} getpwuid uid
Look up an integer userid in the user database.
The following functions accept an object representing group information
and return a selected component:
-@table @code
-@item group:name
+@deffn {Scheme Procedure} group:name gr
The group name.
-@item group:passwd
+@end deffn
+@deffn {Scheme Procedure} group:passwd gr
The encrypted group password.
-@item group:gid
+@end deffn
+@deffn {Scheme Procedure} group:gid gr
The group id number.
-@item group:mem
+@end deffn
+@deffn {Scheme Procedure} group:mem gr
A list of userids which have this group as a supplementary group.
-@end table
+@end deffn
+@sp 1
@deffn {Scheme Procedure} getgrgid gid
Look up an integer group id in the group database.
Return a string containing a user name associated with the
effective user id of the process. Return @code{#f} if this
information cannot be obtained.
+
+This function has been removed from the latest POSIX specification,
+Guile provides it only if the system has it. Using @code{(getpwuid
+(geteuid))} may be a better idea.
@end deffn
@deffn {Scheme Procedure} getlogin
@node Time
-@section Time
+@subsection Time
+@cindex time
@deffn {Scheme Procedure} current-time
@deffnx {C Function} scm_current_time ()
-Return the number of seconds since 1970-01-01 00:00:00 UTC,
+Return the number of seconds since 1970-01-01 00:00:00 @acronym{UTC},
excluding leap seconds.
@end deffn
@deffn {Scheme Procedure} gettimeofday
@deffnx {C Function} scm_gettimeofday ()
Return a pair containing the number of seconds and microseconds
-since 1970-01-01 00:00:00 UTC, excluding leap seconds. Note:
+since 1970-01-01 00:00:00 @acronym{UTC}, excluding leap seconds. Note:
whether true microsecond resolution is available depends on the
operating system.
@end deffn
a broken down time and a value and set the component to the value.
The numbers in parentheses give the usual range.
-@table @code
-@item tm:sec, set-tm:sec
+@deffn {Scheme Procedure} tm:sec tm
+@deffnx {Scheme Procedure} set-tm:sec tm val
Seconds (0-59).
-@item tm:min, set-tm:min
+@end deffn
+@deffn {Scheme Procedure} tm:min tm
+@deffnx {Scheme Procedure} set-tm:min tm val
Minutes (0-59).
-@item tm:hour, set-tm:hour
+@end deffn
+@deffn {Scheme Procedure} tm:hour tm
+@deffnx {Scheme Procedure} set-tm:hour tm val
Hours (0-23).
-@item tm:mday, set-tm:mday
+@end deffn
+@deffn {Scheme Procedure} tm:mday tm
+@deffnx {Scheme Procedure} set-tm:mday tm val
Day of the month (1-31).
-@item tm:mon, set-tm:mon
+@end deffn
+@deffn {Scheme Procedure} tm:mon tm
+@deffnx {Scheme Procedure} set-tm:mon tm val
Month (0-11).
-@item tm:year, set-tm:year
+@end deffn
+@deffn {Scheme Procedure} tm:year tm
+@deffnx {Scheme Procedure} set-tm:year tm val
Year (70-), the year minus 1900.
-@item tm:wday, set-tm:wday
+@end deffn
+@deffn {Scheme Procedure} tm:wday tm
+@deffnx {Scheme Procedure} set-tm:wday tm val
Day of the week (0-6) with Sunday represented as 0.
-@item tm:yday, set-tm:yday
+@end deffn
+@deffn {Scheme Procedure} tm:yday tm
+@deffnx {Scheme Procedure} set-tm:yday tm val
Day of the year (0-364, 365 in leap years).
-@item tm:isdst, set-tm:isdst
-Daylight saving indicator (0 for "no", greater than 0 for "yes", less than
-0 for "unknown").
-@item tm:gmtoff, set-tm:gmtoff
-Time zone offset in seconds west of UTC (-46800 to 43200).
-@item tm:zone, set-tm:zone
+@end deffn
+@deffn {Scheme Procedure} tm:isdst tm
+@deffnx {Scheme Procedure} set-tm:isdst tm val
+Daylight saving indicator (0 for ``no'', greater than 0 for ``yes'', less than
+0 for ``unknown'').
+@end deffn
+@deffn {Scheme Procedure} tm:gmtoff tm
+@deffnx {Scheme Procedure} set-tm:gmtoff tm val
+Time zone offset in seconds west of @acronym{UTC} (-46800 to 43200).
+@end deffn
+@deffn {Scheme Procedure} tm:zone tm
+@deffnx {Scheme Procedure} set-tm:zone tm val
Time zone label (a string), not necessarily unique.
-@end table
+@end deffn
+@sp 1
@deffn {Scheme Procedure} localtime time [zone]
@deffnx {C Function} scm_localtime (time, zone)
+@cindex local time
Return an object representing the broken down components of
@var{time}, an integer like the one returned by
@code{current-time}. The time zone for the calculation is
optionally specified by @var{zone} (a string), otherwise the
-@code{TZ} environment variable or the system default is used.
+@env{TZ} environment variable or the system default is used.
@end deffn
@deffn {Scheme Procedure} gmtime time
@deffnx {C Function} scm_gmtime (time)
Return an object representing the broken down components of
@var{time}, an integer like the one returned by
-@code{current-time}. The values are calculated for UTC.
+@code{current-time}. The values are calculated for @acronym{UTC}.
@end deffn
-@deffn {Scheme Procedure} mktime sbd_time [zone]
+@deffn {Scheme Procedure} mktime sbd-time [zone]
@deffnx {C Function} scm_mktime (sbd_time, zone)
-@var{bd-time} is an object representing broken down time and @code{zone}
-is an optional time zone specifier (otherwise the TZ environment variable
-or the system default is used).
+@var{sbd-time} is an object representing broken down time and
+@code{zone} is an optional time zone specifier (otherwise the @env{TZ}
+environment variable or the system default is used).
-Returns a pair: the car is a corresponding
-integer time value like that returned
-by @code{current-time}; the cdr is a broken down time object, similar to
-as @var{bd-time} but with normalized values.
+Returns a pair: the @acronym{CAR} is a corresponding integer time
+value like that returned by @code{current-time}; the @acronym{CDR} is
+a broken down time object, similar to @var{sbd-time} but with
+normalized values; i.e.@: with corrected @code{tm:wday} and
+@code{tm:yday} fields.
@end deffn
@deffn {Scheme Procedure} tzset
@deffnx {C Function} scm_tzset ()
-Initialize the timezone from the TZ environment variable
+Initialize the timezone from the @env{TZ} environment variable
or the system default. It's not usually necessary to call this procedure
since it's done automatically by other procedures that depend on the
timezone.
@deffn {Scheme Procedure} strftime format stime
@deffnx {C Function} scm_strftime (format, stime)
+@cindex time formatting
Formats a time specification @var{time} using @var{template}. @var{time}
is an object with time components in the form returned by @code{localtime}
or @code{gmtime}. @var{template} is a string which can include formatting
-specifications introduced by a @code{%} character. The formatting of
+specifications introduced by a @samp{%} character. The formatting of
month and day names is dependent on the current locale. The value returned
is the formatted string.
-@xref{Formatting Date and Time, , , libc, The GNU C Library Reference Manual}.)
+@xref{Formatting Calendar Time, , , libc, The GNU C Library Reference Manual}.
@lisp
(strftime "%c" (localtime (current-time)))
@deffn {Scheme Procedure} strptime format string
@deffnx {C Function} scm_strptime (format, string)
+@cindex time parsing
Performs the reverse action to @code{strftime}, parsing
@var{string} according to the specification supplied in
@var{template}. The interpretation of month and day names is
dependent on the current locale. The value returned is a pair.
-The car has an object with time components
+The @acronym{CAR} has an object with time components
in the form returned by @code{localtime} or @code{gmtime},
but the time zone components
are not usefully set.
-The cdr reports the number of characters from @var{string}
+The @acronym{CDR} reports the number of characters from @var{string}
which were used for the conversion.
@end deffn
time. The following procedures accept such an object as an
argument and return a selected component:
-@table @code
-@item tms:clock
+@deffn {Scheme Procedure} tms:clock tms
The current real time, expressed as time units relative to an
arbitrary base.
-@item tms:utime
+@end deffn
+@deffn {Scheme Procedure} tms:utime tms
The CPU time units used by the calling process.
-@item tms:stime
+@end deffn
+@deffn {Scheme Procedure} tms:stime tms
The CPU time units used by the system on behalf of the calling
process.
-@item tms:cutime
+@end deffn
+@deffn {Scheme Procedure} tms:cutime tms
The CPU time units used by terminated child processes of the
calling process, whose status has been collected (e.g., using
@code{waitpid}).
-@item tms:cstime
+@end deffn
+@deffn {Scheme Procedure} tms:cstime tms
Similarly, the CPU times units used by the system on behalf of
terminated child processes.
-@end table
+@end deffn
@end deffn
@deffn {Scheme Procedure} get-internal-real-time
@end deffn
@node Runtime Environment
-@section Runtime Environment
+@subsection Runtime Environment
@deffn {Scheme Procedure} program-arguments
@deffnx {Scheme Procedure} command-line
@deffnx {C Function} scm_program_arguments ()
+@cindex command line
+@cindex program arguments
Return the list of command line arguments passed to Guile, as a list of
strings. The list includes the invoked program name, which is usually
@code{"guile"}, but excludes switches and parameters for command line
@deffn {Scheme Procedure} getenv nam
@deffnx {C Function} scm_getenv (nam)
+@cindex environment
Looks up the string @var{name} in the current environment. The return
value is @code{#f} unless a string of the form @code{NAME=VALUE} is
found, in which case the string @code{VALUE} is returned.
Unix sense) as a list of strings. Otherwise set the current
environment, which is also the default environment for child
processes, to the supplied list of strings. Each member of
-@var{env} should be of the form @code{NAME=VALUE} and values of
-@code{NAME} should not be duplicated. If @var{env} is supplied
+@var{env} should be of the form @var{NAME}=@var{VALUE} and values of
+@var{NAME} should not be duplicated. If @var{env} is supplied
then the return value is unspecified.
@end deffn
@node Processes
-@section Processes
+@subsection Processes
+@cindex processes
+@cindex child processes
@findex cd
@deffn {Scheme Procedure} chdir str
@deffnx {C Function} scm_chdir (str)
+@cindex current directory
Change the current working directory to @var{path}.
The return value is unspecified.
@end deffn
@deffn {Scheme Procedure} umask [mode]
@deffnx {C Function} scm_umask (mode)
-If @var{mode} is omitted, returns a decimal number representing the current
-file creation mask. Otherwise the file creation mask is set to
-@var{mode} and the previous value is returned.
+If @var{mode} is omitted, returns a decimal number representing the
+current file creation mask. Otherwise the file creation mask is set
+to @var{mode} and the previous value is returned. @xref{Setting
+Permissions,,Assigning File Permissions,libc,The GNU C Library
+Reference Manual}, for more on how to use umasks.
-E.g., @code{(umask #o022)} sets the mask to octal 22, decimal 18.
+E.g., @code{(umask #o022)} sets the mask to octal 22/decimal 18.
@end deffn
@deffn {Scheme Procedure} chroot path
system supports effective IDs.
@end deffn
+@deffn {Scheme Procedure} setgroups vec
+@deffnx {C Function} scm_setgroups (vec)
+Set the current set of supplementary group IDs to the integers in the
+given vector @var{vec}. The return value is unspecified.
+
+Generally only the superuser can set the process group IDs
+(@pxref{Setting Groups, Setting the Group IDs,, libc, The GNU C
+Library Reference Manual}).
+@end deffn
+
@deffn {Scheme Procedure} setuid id
@deffnx {C Function} scm_setuid (id)
Sets both the real and effective user IDs to the integer @var{id}, provided
@deffnx {C Function} scm_seteuid (id)
Sets the effective user ID to the integer @var{id}, provided the process
has appropriate privileges. If effective IDs are not supported, the
-real ID is set instead -- @code{(provided? 'EIDs)} reports whether the
+real ID is set instead---@code{(provided? 'EIDs)} reports whether the
system supports effective IDs.
The return value is unspecified.
@end deffn
@deffnx {C Function} scm_setegid (id)
Sets the effective group ID to the integer @var{id}, provided the process
has appropriate privileges. If effective IDs are not supported, the
-real ID is set instead -- @code{(provided? 'EIDs)} reports whether the
+real ID is set instead---@code{(provided? 'EIDs)} reports whether the
system supports effective IDs.
The return value is unspecified.
@end deffn
@deffn {Scheme Procedure} getpgrp
@deffnx {C Function} scm_getpgrp ()
Return an integer representing the current process group ID.
-This is the POSIX definition, not BSD.
+This is the @acronym{POSIX} definition, not @acronym{BSD}.
@end deffn
@deffn {Scheme Procedure} setpgid pid pgid
The value of @var{pid} determines the behaviour:
-@table @r
+@table @asis
@item @var{pid} greater than 0
Request status information from the specified child process.
-@item @var{pid} equal to -1 or WAIT_ANY
+@item @var{pid} equal to -1 or @code{WAIT_ANY}
+@vindex WAIT_ANY
Request status information for any child process.
-@item @var{pid} equal to 0 or WAIT_MYPGRP
+@item @var{pid} equal to 0 or @code{WAIT_MYPGRP}
+@vindex WAIT_MYPGRP
Request status information for any child process in the current process
group.
@item @var{pid} less than -1
Request status information for any child process whose process group ID
-is -@var{PID}.
+is @minus{}@var{pid}.
@end table
The @var{options} argument, if supplied, should be the bitwise OR of the
@deffn {Scheme Procedure} system [cmd]
@deffnx {C Function} scm_system (cmd)
-Execute @var{cmd} using the operating system's "command
-processor". Under Unix this is usually the default shell
+Execute @var{cmd} using the operating system's ``command
+processor''. Under Unix this is usually the default shell
@code{sh}. The value returned is @var{cmd}'s exit status as
returned by @code{waitpid}, which can be interpreted using the
functions above.
indicating whether the command processor is available.
@end deffn
+@deffn {Scheme Procedure} system* . args
+@deffnx {C Function} scm_system_star (args)
+Execute the command indicated by @var{args}. The first element must
+be a string indicating the command to be executed, and the remaining
+items must be strings representing each of the arguments to that
+command.
+
+This function returns the exit status of the command as provided by
+@code{waitpid}. This value can be handled with @code{status:exit-val}
+and the related functions.
+
+@code{system*} is similar to @code{system}, but accepts only one
+string per-argument, and performs no shell interpretation. The
+command is executed using fork and execlp. Accordingly this function
+may be safer than @code{system} in situations where shell
+interpretation is not required.
+
+Example: (system* "echo" "foo" "bar")
+@end deffn
+
@deffn {Scheme Procedure} primitive-exit [status]
@deffnx {C Function} scm_primitive_exit (status)
Terminate the current process without unwinding the Scheme stack.
@deffn {Scheme Procedure} primitive-fork
@deffnx {C Function} scm_fork ()
-Creates a new "child" process by duplicating the current "parent" process.
+Creates a new ``child'' process by duplicating the current ``parent'' process.
In the child the return value is 0. In the parent the return value is
the integer process ID of the child.
@deffn {Scheme Procedure} nice incr
@deffnx {C Function} scm_nice (incr)
+@cindex process priority
Increment the priority of the current process by @var{incr}. A higher
priority value means that the process runs less often.
The return value is unspecified.
@deffn {Scheme Procedure} setpriority which who prio
@deffnx {C Function} scm_setpriority (which, who, prio)
+@vindex PRIO_PROCESS
+@vindex PRIO_PGRP
+@vindex PRIO_USER
Set the scheduling priority of the process, process group
or user, as indicated by @var{which} and @var{who}. @var{which}
is one of the variables @code{PRIO_PROCESS}, @code{PRIO_PGRP}
process group identifier for @code{PRIO_PGRP}, and a user
identifier for @code{PRIO_USER}. A zero value of @var{who}
denotes the current process, process group, or user.
-@var{prio} is a value in the range -20 and 20, the default
-priority is 0; lower priorities cause more favorable
-scheduling. Sets the priority of all of the specified
-processes. Only the super-user may lower priorities.
-The return value is not specified.
+@var{prio} is a value in the range [@minus{}20,20]. The default
+priority is 0; lower priorities (in numerical terms) cause more
+favorable scheduling. Sets the priority of all of the specified
+processes. Only the super-user may lower priorities. The return
+value is not specified.
@end deffn
@deffn {Scheme Procedure} getpriority which who
@deffnx {C Function} scm_getpriority (which, who)
+@vindex PRIO_PROCESS
+@vindex PRIO_PGRP
+@vindex PRIO_USER
Return the scheduling priority of the process, process group
or user, as indicated by @var{which} and @var{who}. @var{which}
is one of the variables @code{PRIO_PROCESS}, @code{PRIO_PGRP}
-or @code{PRIO_USER}, and @var{who} is interpreted relative to
+or @code{PRIO_USER}, and @var{who} should be interpreted depending on
@var{which} (a process identifier for @code{PRIO_PROCESS},
process group identifier for @code{PRIO_PGRP}, and a user
-identifier for @code{PRIO_USER}. A zero value of @var{who}
+identifier for @code{PRIO_USER}). A zero value of @var{who}
denotes the current process, process group, or user. Return
the highest priority (lowest numerical value) of any of the
specified processes.
@node Signals
-@section Signals
+@subsection Signals
+@cindex signal
Procedures to raise, handle and wait for signals.
@var{pid} specifies the processes to which the signal is sent:
-@table @r
+@table @asis
@item @var{pid} greater than 0
The process whose identifier is @var{pid}.
@item @var{pid} equal to 0
@defvar SIGINT
Interrupt signal.
@end defvar
+
+A full list of signals on the GNU system may be found in @ref{Standard
+Signals,,,libc,The GNU C Library Reference Manual}.
@end deffn
@deffn {Scheme Procedure} raise sig
@deffnx {C Function} scm_raise (sig)
Sends a specified signal @var{sig} to the current process, where
-@var{sig} is as described for the kill procedure.
+@var{sig} is as described for the @code{kill} procedure.
@end deffn
-@deffn {Scheme Procedure} sigaction signum [handler [flags]]
+@deffn {Scheme Procedure} sigaction signum [handler [flags [thread]]]
@deffnx {C Function} scm_sigaction (signum, handler, flags)
+@deffnx {C Function} scm_sigaction_for_thread (signum, handler, flags, thread)
Install or report the signal handler for a specified signal.
@var{signum} is the signal number, which can be specified using the value
of variables such as @code{SIGINT}.
-If @var{action} is omitted, @code{sigaction} returns a pair: the
-CAR is the current
-signal hander, which will be either an integer with the value @code{SIG_DFL}
-(default action) or @code{SIG_IGN} (ignore), or the Scheme procedure which
-handles the signal, or @code{#f} if a non-Scheme procedure handles the
-signal. The CDR contains the current @code{sigaction} flags for the handler.
+If @var{handler} is omitted, @code{sigaction} returns a pair: the
+@acronym{CAR} is the current signal hander, which will be either an
+integer with the value @code{SIG_DFL} (default action) or
+@code{SIG_IGN} (ignore), or the Scheme procedure which handles the
+signal, or @code{#f} if a non-Scheme procedure handles the signal.
+The @acronym{CDR} contains the current @code{sigaction} flags for the
+handler.
-If @var{action} is provided, it is installed as the new handler for
-@var{signum}. @var{action} can be a Scheme procedure taking one
+If @var{handler} is provided, it is installed as the new handler for
+@var{signum}. @var{handler} can be a Scheme procedure taking one
argument, or the value of @code{SIG_DFL} (default action) or
@code{SIG_IGN} (ignore), or @code{#f} to restore whatever signal handler
-was installed before @code{sigaction} was first used. Flags can
-optionally be specified for the new handler (@code{SA_RESTART} will
-always be added if it's available and the system is using restartable
-system calls.) The return value is a pair with information about the
-old handler as described above.
+was installed before @code{sigaction} was first used. When a scheme
+procedure has been specified, that procedure will run in the given
+@var{thread}. When no thread has been given, the thread that made this
+call to @code{sigaction} is used.
-This interface does not provide access to the "signal blocking"
+Flags can optionally be specified for the new handler (@code{SA_RESTART}
+will always be added if it's available and the system is using
+restartable system calls.) The return value is a pair with information
+about the old handler as described above.
+
+This interface does not provide access to the ``signal blocking''
facility. Maybe this is not needed, since the thread support may
provide solutions to the problem of consistent access to data
structures.
@deffn {Scheme Procedure} usleep i
@deffnx {C Function} scm_usleep (i)
-Sleep for I microseconds. @code{usleep} is not available on
-all platforms.
+Sleep for @var{i} microseconds. @code{usleep} is not available on
+all platforms. [FIXME: so what happens when it isn't?]
@end deffn
@deffn {Scheme Procedure} setitimer which_timer interval_seconds interval_microseconds value_seconds value_microseconds
@var{value_seconds}, and @var{value_microseconds} values.
Return information about the timer's previous setting.
-Errors are handled as described in the guile info pages under ``POSIX
-Interface Conventions''.
The timers available are: @code{ITIMER_REAL}, @code{ITIMER_VIRTUAL},
and @code{ITIMER_PROF}.
@deffn {Scheme Procedure} getitimer which_timer
@deffnx {C Function} scm_getitimer (which_timer)
-Return information about the timer specified by @var{which_timer}
-Errors are handled as described in the guile info pages under ``POSIX
-Interface Conventions''.
+Return information about the timer specified by @var{which_timer}.
The timers available are: @code{ITIMER_REAL}, @code{ITIMER_VIRTUAL},
and @code{ITIMER_PROF}.
@node Terminals and Ptys
-@section Terminals and Ptys
+@subsection Terminals and Ptys
@deffn {Scheme Procedure} isatty? port
@deffnx {C Function} scm_isatty_p (port)
+@cindex terminal
Return @code{#t} if @var{port} is using a serial non--file
device, otherwise @code{#f}.
@end deffn
@deffn {Scheme Procedure} ttyname port
@deffnx {C Function} scm_ttyname (port)
+@cindex terminal
Return a string with the name of the serial terminal device
underlying @var{port}.
@end deffn
@deffn {Scheme Procedure} ctermid
@deffnx {C Function} scm_ctermid ()
+@cindex terminal
Return a string containing the file name of the controlling
terminal for the current process.
@end deffn
@deffn {Scheme Procedure} tcgetpgrp port
@deffnx {C Function} scm_tcgetpgrp (port)
+@cindex process group
Return the process group ID of the foreground process group
associated with the terminal open on the file descriptor
underlying @var{port}.
@deffn {Scheme Procedure} tcsetpgrp port pgid
@deffnx {C Function} scm_tcsetpgrp (port, pgid)
+@cindex process group
Set the foreground process group ID for the terminal used by the file
descriptor underlying @var{port} to the integer @var{pgid}.
The calling process
@end deffn
@node Pipes
-@section Pipes
+@subsection Pipes
+@cindex pipe
-The following procedures provide an interface to the @code{popen} and
-@code{pclose} system routines. The code is in a separate "popen"
+The following procedures are similar to the @code{popen} and
+@code{pclose} system routines. The code is in a separate ``popen''
module:
@smalllisp
@end smalllisp
@findex popen
-@deffn {Scheme Procedure} open-pipe command modes
-Executes the shell command @var{command} (a string) in a subprocess.
-A pipe to the process is created and returned. @var{modes} specifies
-whether an input or output pipe to the process is created: it should
-be the value of @code{OPEN_READ} or @code{OPEN_WRITE}.
+@deffn {Scheme Procedure} open-pipe command mode
+@deffnx {Scheme Procedure} open-pipe* mode prog [args...]
+Execute a command in a subprocess, with a pipe to it or from it, or
+with pipes in both directions.
+
+@code{open-pipe} runs the shell @var{command} using @samp{/bin/sh -c}.
+@code{open-pipe*} executes @var{prog} directly, with the optional
+@var{args} arguments (all strings).
+
+@var{mode} should be one of the following values. @code{OPEN_READ} is
+an input pipe, ie.@: to read from the subprocess. @code{OPEN_WRITE}
+is an output pipe, ie.@: to write to it.
+
+@defvar OPEN_READ
+@defvarx OPEN_WRITE
+@defvarx OPEN_BOTH
+@end defvar
+
+For an input pipe, the child's standard output is the pipe and
+standard input is inherited from @code{current-input-port}. For an
+output pipe, the child's standard input is the pipe and standard
+output is inherited from @code{current-output-port}. In all cases
+cases the child's standard error is inherited from
+@code{current-error-port} (@pxref{Default Ports}).
+
+If those @code{current-X-ports} are not files of some kind, and hence
+don't have file descriptors for the child, then @file{/dev/null} is
+used instead.
+
+Care should be taken with @code{OPEN_BOTH}, a deadlock will occur if
+both parent and child are writing, and waiting until the write
+completes before doing any reading. Each direction has
+@code{PIPE_BUF} bytes of buffering (@pxref{Ports and File
+Descriptors}), which will be enough for small writes, but not for say
+putting a big file through a filter.
@end deffn
@deffn {Scheme Procedure} open-input-pipe command
Equivalent to @code{open-pipe} with mode @code{OPEN_READ}.
@lisp
-(read-line (open-input-pipe "date"))
-@result{} "Mon Mar 11 20:10:44 GMT 2002"
-
-(waitpid WAIT_ANY)
-@result{} (24160 . 0)
+(let* ((port (open-input-pipe "date --utc"))
+ (str (read-line port)))
+ (close-pipe port)
+ str)
+@result{} "Mon Mar 11 20:10:44 UTC 2002"
@end lisp
@end deffn
@deffn {Scheme Procedure} open-output-pipe command
Equivalent to @code{open-pipe} with mode @code{OPEN_WRITE}.
+
+@lisp
+(let ((port (open-output-pipe "lpr")))
+ (display "Something for the line printer.\n" port)
+ (if (not (eqv? 0 (status:exit-val (close-pipe port))))
+ (error "Cannot print")))
+@end lisp
+@end deffn
+
+@deffn {Scheme Procedure} open-input-output-pipe command
+Equivalent to @code{open-pipe} with mode @code{OPEN_BOTH}.
@end deffn
@findex pclose
@deffn {Scheme Procedure} close-pipe port
-Closes the pipe created by @code{open-pipe}, then waits for the process
-to terminate and returns its status value, @xref{Processes, waitpid}, for
-information on how to interpret this value.
-
-@code{close-port} (@pxref{Closing, close-port}) can also be used to
-close a pipe, but doesn't return the status.
+Close a pipe created by @code{open-pipe}, wait for the process to
+terminate, and return the wait status code. The status is as per
+@code{waitpid} and can be decoded with @code{status:exit-val} etc
+(@pxref{Processes})
@end deffn
+@sp 1
+@code{waitpid WAIT_ANY} should not be used when pipes are open, since
+it can reap a pipe's child process, causing an error from a subsequent
+@code{close-pipe}.
+
+@code{close-port} (@pxref{Closing}) can close a pipe, but it doesn't
+reap the child process.
+
+The garbage collector will close a pipe no longer in use, and reap the
+child process with @code{waitpid}. If the child hasn't yet terminated
+the garbage collector doesn't block, but instead checks again in the
+next GC.
+
+Many systems have per-user and system-wide limits on the number of
+processes, and a system-wide limit on the number of pipes, so pipes
+should be closed explicitly when no longer needed, rather than letting
+the garbage collector pick them up at some later time.
+
+
@node Networking
-@section Networking
+@subsection Networking
+@cindex network
@menu
* Network Address Conversion::
@end menu
@node Network Address Conversion
-@subsection Network Address Conversion
+@subsubsection Network Address Conversion
+@cindex network address
This section describes procedures which convert internet addresses
between numeric and string formats.
-@subsubsection IPv4 Address Conversion
+@subsubheading IPv4 Address Conversion
+@cindex IPv4
+
+An IPv4 Internet address is a 4-byte value, represented in Guile as an
+integer in network byte order (meaning the first byte is the most
+significant in the number).
+
+@defvar INADDR_LOOPBACK
+The address of the local host using the loopback device, ie.@:
+@samp{127.0.0.1}.
+@end defvar
+
+@defvar INADDR_BROADCAST
+The broadcast address on the local network.
+@end defvar
+
+@c INADDR_NONE is defined in the code, but serves no purpose.
+@c inet_addr() returns it as an error indication, but that function
+@c isn't provided, for the good reason that inet_aton() does the same
+@c job and gives an unambiguous error indication. (INADDR_NONE is a
+@c valid 4-byte value, in glibc it's the same as INADDR_BROADCAST.)
+@c
+@c @defvar INADDR_NONE
+@c No address.
+@c @end defvar
@deffn {Scheme Procedure} inet-aton address
@deffnx {C Function} scm_inet_aton (address)
@end lisp
@end deffn
-@subsubsection IPv6 Address Conversion
+@subsubheading IPv6 Address Conversion
+@cindex IPv6
@deffn {Scheme Procedure} inet-ntop family address
@deffnx {C Function} scm_inet_ntop (family, address)
@node Network Databases
-@subsection Network Databases
+@subsubsection Network Databases
+@cindex network database
This section describes procedures which query various network databases.
Care should be taken when using the database routines since they are not
reentrant.
-@subsubsection The Host Database
+@subsubheading The Host Database
+@cindex @file{/etc/hosts}
+@cindex network database
A @dfn{host object} is a structure that represents what is known about a
network host, and is the usual way of representing a system's network
component:
@deffn {Scheme Procedure} hostent:name host
-The "official" hostname for @var{host}.
+The ``official'' hostname for @var{host}.
@end deffn
@deffn {Scheme Procedure} hostent:aliases host
A list of aliases for @var{host}.
If @var{stayopen} is omitted, this is equivalent to @code{endhostent}.
Otherwise it is equivalent to @code{sethostent stayopen}.
@end deffn
-@subsubsection The Network Database
+
+@subsubheading The Network Database
+@cindex network database
The following functions accept an object representing a network
and return a selected component:
@deffn {Scheme Procedure} netent:name net
-The "official" network name.
+The ``official'' network name.
@end deffn
@deffn {Scheme Procedure} netent:aliases net
A list of aliases for the network.
Otherwise it is equivalent to @code{setnetent stayopen}.
@end deffn
-@subsubsection The Protocol Database
+@subsubheading The Protocol Database
+@cindex @file{/etc/protocols}
+@cindex protocols
+@cindex network protocols
The following functions accept an object representing a protocol
and return a selected component:
@deffn {Scheme Procedure} protoent:name protocol
-The "official" protocol name.
+The ``official'' protocol name.
@end deffn
@deffn {Scheme Procedure} protoent:aliases protocol
A list of aliases for the protocol.
Otherwise it is equivalent to @code{setprotoent stayopen}.
@end deffn
-@subsubsection The Service Database
+@subsubheading The Service Database
+@cindex @file{/etc/services}
+@cindex services
+@cindex network services
The following functions accept an object representing a service
and return a selected component:
@deffn {Scheme Procedure} servent:name serv
-The "official" name of the network service.
+The ``official'' name of the network service.
@end deffn
@deffn {Scheme Procedure} servent:aliases serv
A list of aliases for the network service.
@end deffn
@node Network Sockets and Communication
-@subsection Network Sockets and Communication
+@subsubsection Network Sockets and Communication
+@cindex socket
+@cindex network socket
Socket ports can be created using @code{socket} and @code{socketpair}.
The ports are initially unbuffered, to make reading and writing to the
same port more reliable. A buffer can be added to the port using
-@code{setvbuf}, @xref{Ports and File Descriptors}.
+@code{setvbuf}; see @ref{Ports and File Descriptors}.
+
+Most systems have limits on how many files and sockets can be open, so
+it's strongly recommended that socket ports be closed explicitly when
+no longer required (@pxref{Ports}).
-The convention used for "host" vs "network" addresses is that addresses
-are always held in host order at the Scheme level. The procedures in
-this section automatically convert between host and network order when
-required. The arguments and return values are thus in host order.
+The convention used for ``host'' vs.@: ``network'' addresses is that
+addresses are always held in host order at the Scheme level. The
+procedures in this section automatically convert between host and
+network order when required. The arguments and return values are thus
+in host order.
@deffn {Scheme Procedure} socket family style proto
@deffnx {C Function} scm_socket (family, style, proto)
Return a new socket port of the type specified by @var{family},
-@var{style} and @var{proto}. All three parameters are
-integers. Supported values for @var{family} are
-@code{AF_UNIX}, @code{AF_INET} and @code{AF_INET6}.
-Typical values for @var{style} are @code{SOCK_STREAM},
-@code{SOCK_DGRAM} and @code{SOCK_RAW}.
+@var{style} and @var{proto}. All three parameters are integers. The
+possible values for @var{family} are as follows, where supported by
+the system,
+
+@defvar PF_UNIX
+@defvarx PF_INET
+@defvarx PF_INET6
+@end defvar
+
+The possible values for @var{style} are as follows, again where
+supported by the system,
+
+@defvar SOCK_STREAM
+@defvarx SOCK_DGRAM
+@defvarx SOCK_RAW
+@defvarx SOCK_RDM
+@defvarx SOCK_SEQPACKET
+@end defvar
@var{proto} can be obtained from a protocol name using
-@code{getprotobyname}. A value of zero specifies the default
-protocol, which is usually right.
+@code{getprotobyname} (@pxref{Network Databases}). A value of zero
+means the default protocol, which is usually right.
-A single socket port cannot by used for communication until it
-has been connected to another socket.
+A socket cannot by used for communication until it has been connected
+somewhere, usually with either @code{connect} or @code{accept} below.
@end deffn
@deffn {Scheme Procedure} socketpair family style proto
@deffnx {C Function} scm_socketpair (family, style, proto)
-Return a pair of connected (but unnamed) socket ports of the
-type specified by @var{family}, @var{style} and @var{proto}.
-Many systems support only socket pairs of the @code{AF_UNIX}
-family. Zero is likely to be the only meaningful value for
-@var{proto}.
+Return a pair, the @code{car} and @code{cdr} of which are two unnamed
+socket ports connected to each other. The connection is full-duplex,
+so data can be transferred in either direction between the two.
+
+@var{family}, @var{style} and @var{proto} are as per @code{socket}
+above. But many systems only support socket pairs in the
+@code{PF_UNIX} family. Zero is likely to be the only meaningful value
+for @var{proto}.
@end deffn
@deffn {Scheme Procedure} getsockopt sock level optname
set on the socket.
The return value is a
-pair in which the @emph{car} is a new socket port for the
+pair in which the @acronym{CAR} is a new socket port for the
connection and
-the @emph{cdr} is an object with address information about the
+the @acronym{CDR} is an object with address information about the
client which initiated the connection.
@var{sock} does not become part of the
The following functions take a socket address object, as returned
by @code{accept} and other procedures, and return a selected component.
-@table @code
-@item sockaddr:fam
+@deffn {Scheme Procedure} sockaddr:fam sa
The socket family, typically equal to the value of @code{AF_UNIX} or
@code{AF_INET}.
-@item sockaddr:path
+@end deffn
+@deffn {Scheme Procedure} sockaddr:path sa
If the socket family is @code{AF_UNIX}, returns the path of the
filename the socket is based on.
-@item sockaddr:addr
+@end deffn
+@deffn {Scheme Procedure} sockaddr:addr sa
If the socket family is @code{AF_INET}, returns the Internet host
address.
-@item sockaddr:port
+@end deffn
+@deffn {Scheme Procedure} sockaddr:port sa
If the socket family is @code{AF_INET}, returns the Internet port
number.
-@end table
+@end deffn
@deffn {Scheme Procedure} getsockname sock
@deffnx {C Function} scm_getsockname (sock)
then some data
will be irrevocably lost.
-The optional @var{flags} argument is a value or
-bitwise OR of MSG_OOB, MSG_PEEK, MSG_DONTROUTE etc.
+@vindex MSG_OOB
+@vindex MSG_PEEK
+@vindex MSG_DONTROUTE
+The optional @var{flags} argument is a value or bitwise OR of
+@code{MSG_OOB}, @code{MSG_PEEK}, @code{MSG_DONTROUTE} etc.
The value returned is the number of bytes read from the
socket.
@deffn {Scheme Procedure} send sock message [flags]
@deffnx {C Function} scm_send (sock, message, flags)
+@vindex MSG_OOB
+@vindex MSG_PEEK
+@vindex MSG_DONTROUTE
Transmit the string @var{message} on a socket port @var{sock}.
-@var{sock} must already be bound to a destination address. The
-value returned is the number of bytes transmitted --
-it's possible for
-this to be less than the length of @var{message}
-if the socket is
-set to be non-blocking. The optional @var{flags} argument
-is a value or
-bitwise OR of MSG_OOB, MSG_PEEK, MSG_DONTROUTE etc.
+@var{sock} must already be bound to a destination address. The value
+returned is the number of bytes transmitted---it's possible for this
+to be less than the length of @var{message} if the socket is set to be
+non-blocking. The optional @var{flags} argument is a value or bitwise
+OR of @code{MSG_OOB}, @code{MSG_PEEK}, @code{MSG_DONTROUTE} etc.
Note that the data is written directly to the socket
file descriptor:
if a packet larger than this limit is encountered then some
data will be irrevocably lost.
+@vindex MSG_OOB
+@vindex MSG_PEEK
+@vindex MSG_DONTROUTE
The optional @var{flags} argument is a value or bitwise OR of
@code{MSG_OOB}, @code{MSG_PEEK}, @code{MSG_DONTROUTE} etc.
-The value returned is a pair: the @emph{car} is the number of
-bytes read from the socket and the @emph{cdr} an address object
+The value returned is a pair: the @acronym{CAR} is the number of
+bytes read from the socket and the @acronym{CDR} an address object
in the same form as returned by @code{accept}. The address
will given as @code{#f} if not available, as is usually the
case for stream sockets.
@code{connect} procedure. @var{args_and_flags} contains
the usual connection arguments optionally followed by
a flags argument, which is a value or
-bitwise OR of MSG_OOB, MSG_PEEK, MSG_DONTROUTE etc.
+bitwise OR of @code{MSG_OOB}, @code{MSG_PEEK}, @code{MSG_DONTROUTE} etc.
The value returned is the number of bytes transmitted --
it's possible for
@end deffn
The following functions can be used to convert short and long integers
-between "host" and "network" order. Although the procedures above do
+between ``host'' and ``network'' order. Although the procedures above do
this automatically for addresses, the conversion will still need to
be done when sending or receiving encoded integer data from the network.
@node Internet Socket Examples
-@subsection Network Socket Examples
-
-The following sections give examples of how to use network sockets.
-
-@menu
-* Internet Socket Client::
-* Internet Socket Server::
-@end menu
+@subsubsection Network Socket Examples
+@cindex network examples
+@cindex socket examples
+The following give examples of how to use network sockets.
-@node Internet Socket Client
-@subsubsection Internet Socket Client Example
+@subsubheading Internet Socket Client Example
@cindex socket client example
The following example demonstrates an Internet socket client.
returns the contents of the root index URL.
@example
-(let ((s (socket AF_INET SOCK_STREAM 0)))
+(let ((s (socket PF_INET SOCK_STREAM 0)))
(connect s AF_INET (inet-aton "127.0.0.1") 80)
(display "GET / HTTP/1.0\r\n\r\n" s)
@end example
-@node Internet Socket Server
-@subsubsection Internet Socket Server Example
+@subsubheading Internet Socket Server Example
@cindex socket server example
The following example shows a simple Internet server which listens on
client.
@example
-(let ((s (socket AF_INET SOCK_STREAM 0)))
+(let ((s (socket PF_INET SOCK_STREAM 0)))
(setsockopt s SOL_SOCKET SO_REUSEADDR 1)
- ;; Specific address?
- ;; (bind s AF_INET (inet-aton "127.0.0.1") 2904)
+ ;; @r{Specific address?}
+ ;; @r{(bind s AF_INET (inet-aton "127.0.0.1") 2904)}
(bind s AF_INET INADDR_ANY 2904)
(listen s 5)
(gethostbyaddr
(sockaddr:addr client-details)))
(newline)
- ;; Send back the greeting to the client port
+ ;; @r{Send back the greeting to the client port}
(display "Hello client\r\n" client)
(close client))))
@end example
@node System Identification
-@section System Identification
+@subsection System Identification
+@cindex system name
This section lists the various procedures Guile provides for accessing
information about the system it runs on.
@deffnx {C Function} scm_uname ()
Return an object with some information about the computer
system the program is running on.
-@end deffn
The following procedures accept an object as returned by @code{uname}
and return a selected component.
-@table @code
-@item utsname:sysname
+@deffn {Scheme Procedure} utsname:sysname un
The name of the operating system.
-@item utsname:nodename
+@end deffn
+@deffn {Scheme Procedure} utsname:nodename un
The network name of the computer.
-@item utsname:release
+@end deffn
+@deffn {Scheme Procedure} utsname:release un
The current release level of the operating system implementation.
-@item utsname:version
+@end deffn
+@deffn {Scheme Procedure} utsname:version un
The current version level within the release of the operating system.
-@item utsname:machine
+@end deffn
+@deffn {Scheme Procedure} utsname:machine un
A description of the hardware.
-@end table
+@end deffn
+@end deffn
@deffn {Scheme Procedure} gethostname
@deffnx {C Function} scm_gethostname ()
+@cindex host name
Return the host name of the current processor.
@end deffn
specified.
@end deffn
-@c FIXME::martin: Not in libguile!
-@deffn {Scheme Procedure} software-type
-Return a symbol describing the current platform's operating system.
-This may be one of AIX, VMS, UNIX, COHERENT, WINDOWS, MS-DOS, OS/2,
-THINKC, AMIGA, ATARIST, MACH, or ACORN.
-
-Note that most varieties of Unix are considered to be simply "UNIX".
-That is because when a program depends on features that are not present
-on every operating system, it is usually better to test for the presence
-or absence of that specific feature. The return value of
-@code{software-type} should only be used for this purpose when there is
-no other easy or unambiguous way of detecting such features.
-@end deffn
-
@node Locales
-@section Locales
+@subsection Locales
+@cindex locale
@deffn {Scheme Procedure} setlocale category [locale]
@deffnx {C Function} scm_setlocale (category, locale)
-If @var{locale} is omitted, return the current value of the
-specified locale category as a system-dependent string.
-@var{category} should be specified using the values
-@code{LC_COLLATE}, @code{LC_ALL} etc.
+Get or set the current locale, used for various internationalizations.
+Locales are strings, such as @samp{sv_SE}.
+
+If @var{locale} is given then the locale for the given @var{category} is set
+and the new value returned. If @var{locale} is not given then the
+current value is returned. @var{category} should be one of the
+following values
+
+@defvar LC_ALL
+@defvarx LC_COLLATE
+@defvarx LC_CTYPE
+@defvarx LC_MESSAGES
+@defvarx LC_MONETARY
+@defvarx LC_NUMERIC
+@defvarx LC_TIME
+@end defvar
-Otherwise the specified locale category is set to the string
-@var{locale} and the new value is returned as a
-system-dependent string. If @var{locale} is an empty string,
-the locale will be set using environment variables.
+@cindex @code{LANG}
+A common usage is @samp{(setlocale LC_ALL "")}, which initializes all
+categories based on standard environment variables (@code{LANG} etc).
+For full details on categories and locale names @pxref{Locales,,
+Locales and Internationalization, libc, The GNU C Library Reference
+Manual}.
@end deffn
@node Encryption
-@section Encryption
+@subsection Encryption
+@cindex encryption
Please note that the procedures in this section are not suited for
strong encryption, they are only interfaces to the well-known and
@deffn {Scheme Procedure} getpass prompt
@deffnx {C Function} scm_getpass (prompt)
+@cindex password
Display @var{prompt} to the standard error output and read
a password from @file{/dev/tty}. If this file is not
accessible, it reads from standard input. The password may be
the password, echoing and the generation of signals by special
characters is disabled.
@end deffn
+
+
+@c Local Variables:
+@c TeX-master: "guile.texi"
+@c End:
HCoop / bpt / guile.git / blobdiff