Merge from emacs-24; up to 2012-04-21T14:12:27Z!sdl.web@gmail.com

[bpt/emacs.git] / doc / lispref / errors.texi

@c -*-texinfo-*-
@c This is part of the GNU Emacs Lisp Reference Manual.
@c Copyright (C) 1990-1993, 1999, 2001-2012 Free Software Foundation, Inc.
@c See the file elisp.texi for copying conditions.
@node Standard Errors, Standard Keymaps, GNU Emacs Internals, Top
@appendix Standard Errors
@cindex standard errors

  Here is a list of the more important error symbols in standard Emacs,
grouped by concept.  The list includes each symbol's message (on the
@code{error-message} property of the symbol) and a cross reference to a
description of how the error can occur.

  Each error symbol has an @code{error-conditions} property that is a
list of symbols.  Normally this list includes the error symbol itself
and the symbol @code{error}.  Occasionally it includes additional
symbols, which are intermediate classifications, narrower than
@code{error} but broader than a single error symbol.  For example, all
the errors in accessing files have the condition @code{file-error}.  If
we do not say here that a certain error symbol has additional error
conditions, that means it has none.

  As a special exception, the error symbol @code{quit} does not have the
condition @code{error}, because quitting is not considered an error.

@c You can grep for "(put 'foo 'error-conditions ...) to find
@c examples defined in Lisp.  Eg soap-client.el, sasl.el.
  Most of these error symbols are defined in C (mainly @file{data.c}),
but some are defined in Lisp.  For example, the file @file{userlock.el}
defines the @code{file-locked} and @code{file-supersession} errors.
Several of the specialized Lisp libraries distributed with Emacs
define their own error symbols.  We do not attempt to list of all
those here.

  @xref{Errors}, for an explanation of how errors are generated and
handled.

@table @code
@item error
@code{"error"}@*
@xref{Errors}.

@item quit
@code{"Quit"}@*
@xref{Quitting}.

@item args-out-of-range
@code{"Args out of range"}@*
This happens when trying to access an element beyond the range of a
sequence or buffer.@*
@xref{Sequences Arrays Vectors}, @xref{Text}.

@item arith-error
@code{"Arithmetic error"}@*
@xref{Arithmetic Operations}.

@item beginning-of-buffer
@code{"Beginning of buffer"}@*
@xref{Character Motion}.

@item buffer-read-only
@code{"Buffer is read-only"}@*
@xref{Read Only Buffers}.

@item circular-list
@code{"List contains a loop"}@*
This happens when some operations (e.g. resolving face names)
encounter circular structures.@*
@xref{Circular Objects}.

@item cl-assertion-failed
@code{"Assertion failed"}@*
This happens when the @code{assert} macro fails a test.@*
@xref{Assertions,,, cl, Common Lisp Extensions}.

@item coding-system-error
@code{"Invalid coding system"}@*
@xref{Lisp and Coding Systems}.

@item cyclic-function-indirection
@code{"Symbol's chain of function indirections contains a loop"}@*
@xref{Function Indirection}.

@item cyclic-variable-indirection
@code{"Symbol's chain of variable indirections contains a loop"}@*
@xref{Variable Aliases}.

@item dbus-error
@code{"D-Bus error"}@*
This is only defined if Emacs was compiled with D-Bus support.@*
@xref{Errors and Events,,, dbus, D-Bus integration in Emacs}.

@item end-of-buffer
@code{"End of buffer"}@*
@xref{Character Motion}.

@item end-of-file
@code{"End of file during parsing"}@*
Note that this is not a subcategory of @code{file-error},
because it pertains to the Lisp reader, not to file I/O.@*
@xref{Input Functions}.

@item file-already-exists
This is a subcategory of @code{file-error}.@*
@xref{Writing to Files}.

@item file-date-error
This is a subcategory of @code{file-error}.  It occurs when
@code{copy-file} tries and fails to set the last-modification time of
the output file.@*
@xref{Changing Files}.

@item file-error
We do not list the error-strings of this error and its subcategories,
because the error message is normally constructed from the data items
alone when the error condition @code{file-error} is present.  Thus,
the error-strings are not very relevant.  However, these error symbols
do have @code{error-message} properties, and if no data is provided,
the @code{error-message} property @emph{is} used.@*
@xref{Files}.

@c jka-compr.el
@item compression-error
This is a subcategory of @code{file-error}, which results from
problems handling a compressed file.@*
@xref{How Programs Do Loading}.

@c userlock.el
@item file-locked
This is a subcategory of @code{file-error}.@*
@xref{File Locks}.

@c userlock.el
@item file-supersession
This is a subcategory of @code{file-error}.@*
@xref{Modification Time}.

@c net/ange-ftp.el
@item ftp-error
This is a subcategory of @code{file-error}, which results from problems
in accessing a remote file using ftp.@*
@xref{Remote Files,,, emacs, The GNU Emacs Manual}.

@item invalid-function
@code{"Invalid function"}@*
@xref{Function Indirection}.

@item invalid-read-syntax
@code{"Invalid read syntax"}@*
@xref{Printed Representation}.

@item invalid-regexp
@code{"Invalid regexp"}@*
@xref{Regular Expressions}.

@c simple.el
@item mark-inactive
@code{"The mark is not active now"}@*
@xref{The Mark}.

@item no-catch
@code{"No catch for tag"}@*
@xref{Catch and Throw}.

@ignore
@c Not actually used for anything?  Probably definition should be removed.
@item protected-field
@code{"Attempt to modify a protected field"}
@end ignore

@item scan-error
@code{"Scan error"}@*
This happens when certain syntax-parsing functions
find invalid syntax or mismatched parentheses.@*
@xref{List Motion}, and @ref{Parsing Expressions}.

@item search-failed
@code{"Search failed"}@*
@xref{Searching and Matching}.

@item setting-constant
@code{"Attempt to set a constant symbol"}@*
The values of the symbols @code{nil} and @code{t},
and any symbols that start with @samp{:},
may not be changed.@*
@xref{Constant Variables, , Variables that Never Change}.

@c simple.el
@item text-read-only
@code{"Text is read-only"}@*
This is a subcategory of @code{buffer-read-only}.@*
@xref{Special Properties}.

@item undefined-color
@code{"Undefined color"}@*
@xref{Color Names}.

@item void-function
@code{"Symbol's function definition is void"}@*
@xref{Function Cells}.

@item void-variable
@code{"Symbol's value as variable is void"}@*
@xref{Accessing Variables}.

@item wrong-number-of-arguments
@code{"Wrong number of arguments"}@*
@xref{Classifying Lists}.

@item wrong-type-argument
@code{"Wrong type argument"}@*
@xref{Type Predicates}.
@end table

  The following kinds of error, which are classified as special cases of
@code{arith-error}, can occur on certain systems for invalid use of
mathematical functions.  @xref{Math Functions}.

@table @code
@item domain-error
@code{"Arithmetic domain error"}

@item overflow-error
@code{"Arithmetic overflow error"}@*
This is a subcategory of @code{domain-error}.

@item range-error
@code{"Arithmetic range error"}

@item singularity-error
@code{"Arithmetic singularity error"}@*
This is a subcategory of @code{domain-error}.

@item underflow-error
@code{"Arithmetic underflow error"}@*
This is a subcategory of @code{domain-error}.
@end table