argument that specifies where the standard output from the program will
go. It should be a buffer or a buffer name; if it is a buffer name,
that will create the buffer if it does not already exist. It can also
-be @code{nil}, which says to discard the output unless a filter function
+be @code{nil}, which says to discard the output, unless a custom filter function
handles it. (@xref{Filter Functions}, and @ref{Read and Print}.)
Normally, you should avoid having multiple processes send output to the
same buffer because their output would be intermixed randomly.
@cindex process output
@cindex output from processes
- There are two ways to receive the output that a subprocess writes to
-its standard output stream. The output can be inserted in a buffer,
-which is called the associated buffer of the process (@pxref{Process
-Buffers}), or a function called the @dfn{filter function} can be
-called to act on the output. If the process has no buffer and no
-filter function, its output is discarded.
+ The output that a subprocess writes to its standard output stream
+is passed to a function called the @dfn{filter function}. The default
+filter function simply inserts the output into a buffer, which is
+called the associated buffer of the process (@pxref{Process
+Buffers}). If the process has no buffer then the default filter
+discards the output.
When a subprocess terminates, Emacs reads any pending output,
then stops reading output from that subprocess. Therefore, if the
By default, process output is inserted in the associated buffer.
(You can change this by defining a custom filter function,
-@pxref{Filter Functions}). The position to insert the output is
+@pxref{Filter Functions}.) The position to insert the output is
determined by the @code{process-mark}, which is then updated to point
to the end of the text just inserted. Usually, but not always, the
@code{process-mark} is at the end of the buffer.
If @var{process} does not have a buffer, @code{process-mark} returns a
marker that points nowhere.
-Insertion of process output in a buffer uses this marker to decide where
-to insert, and updates it to point after the inserted text. That is why
-successive batches of output are inserted consecutively.
+The default filter function uses this marker to decide where to
+insert process output, and updates it to point after the inserted text.
+That is why successive batches of output are inserted consecutively.
-Filter functions normally should use this marker in the same fashion
-as is done by direct insertion of output in the buffer. For an
-example of a filter function that uses @code{process-mark},
+Custom filter functions normally should use this marker in the same fashion.
+For an example of a filter function that uses @code{process-mark},
@pxref{Process Filter Example}.
When the user is expected to enter input in the process buffer for
@cindex process filter
A process @dfn{filter function} is a function that receives the
-standard output from the associated process. @emph{all} output from
+standard output from the associated process. @emph{All} output from
that process is passed to the filter. The default filter simply
outputs directly to the process buffer.
@xref{Query Before Exit}.
@item :filter @var{filter}
-Initialize the process filter to @var{filter}. (Otherwise the default
-filter is used.)
+Initialize the process filter to @var{filter}.
@item :filter-multibyte @var{multibyte}
If @var{multibyte} is non-@code{nil}, strings given to the process
default value of @code{enable-multibyte-characters}.
@item :sentinel @var{sentinel}
-Initialize the process sentinel to @var{sentinel}. (Otherwise the default
-sentinel is used.)
+Initialize the process sentinel to @var{sentinel}.
@item :log @var{log}
Initialize the log function of a server process to @var{log}. The log
@code{stop-process}.
@item :filter @var{filter}
-Install @var{filter} as the process filter. (Otherwise the default
-filter is used.)
+Install @var{filter} as the process filter.
@item :sentinel @var{sentinel}
-Install @var{sentinel} as the process sentinel. (Otherwise the default
-sentinel is used.)
+Install @var{sentinel} as the process sentinel.
@item :plist @var{plist}
Install @var{plist} as the initial plist of the process.
HCoop / bpt / emacs.git / blobdiff