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[Emacs-diffs] Changes to emacs/doc/lispref/functions.texi,v
From: |
Glenn Morris |
Subject: |
[Emacs-diffs] Changes to emacs/doc/lispref/functions.texi,v |
Date: |
Sat, 24 Nov 2007 03:06:15 +0000 |
CVSROOT: /sources/emacs
Module name: emacs
Changes by: Glenn Morris <gm> 07/11/24 03:06:15
Index: functions.texi
===================================================================
RCS file: /sources/emacs/emacs/doc/lispref/functions.texi,v
retrieving revision 1.3
retrieving revision 1.4
diff -u -b -r1.3 -r1.4
--- functions.texi 27 Oct 2007 09:07:15 -0000 1.3
+++ functions.texi 24 Nov 2007 03:06:15 -0000 1.4
@@ -23,6 +23,7 @@
of a symbol.
* Obsolete Functions:: Declaring functions obsolete.
* Inline Functions:: Defining functions that the compiler will open code.
+* Declaring Functions:: Telling the compiler that a function is defined.
* Function Safety:: Determining whether a function is safe to call.
* Related Topics:: Cross-references to specific Lisp primitives
that have a special bearing on how functions work.
@@ -1222,6 +1223,56 @@
Inline functions can be used and open-coded later on in the same file,
following the definition, just like macros.
address@hidden Declaring Functions
address@hidden Telling the Compiler that a Function is Defined
address@hidden function declaration
address@hidden declaring functions
+
+Byte-compiling a file often produces warnings about functions that are
address@hidden known to be defined} (@pxref{Compiler Errors}). The compiler
+is technically correct, but the code is usually such that when it
+actually runs, the function @emph{will} be defined. For example,
+byte-compiling @file{fortran.el} used to warn:
+
address@hidden
+In end of data:
+fortran.el:2152:1:Warning: the function `gud-find-c-expr' is not known
+to be defined.
address@hidden example
+
+But @code{gud-find-c-expr} is only used in the function that Fortran
+mode uses for the local value of @code{gud-find-expr-function}. This
+would only ever be called from gud, so the warning can safely be
+suppressed. It's nice to do this, so that real warnings are more
+visible.
+
+All you need to do is add a @code{declare-function} statement before the
+first use of the function in question:
+
address@hidden
+(declare-function gud-find-c-expr "gud.el" nil)
address@hidden example
+
+This says that @code{gud-find-c-expr} is defined in @file{gud.el} (the
+`.el' can be omitted). The file is searched for using
address@hidden, and failing that it is expanded relative to the
+file containing the @code{declare-function} statement. Functions
+defined in C can also be declared - @file{.c} files are expanded
+relative to the Emacs @file{src/} directory.
+
+The optional third argument specifies the argument list of
address@hidden In this case, it takes no arguments (@code{nil}
+is different from not specifying a value). In other cases, this might
+be something like @code{(file &optional overwrite)}. You don't have to
+specify the argument list, but if you do the byte-compiler will check
+that the calls match the declaration.
+
+The functions @code{check-declare-file} and
address@hidden check that all the
address@hidden statements in a file or directory are true
+(i.e. that the functions @emph{are} defined in the specified files, and
+have matching argument lists, if these were specified).
+
@node Function Safety
@section Determining whether a Function is Safe to Call
@cindex function safety
- [Emacs-diffs] Changes to emacs/doc/lispref/functions.texi,v,
Glenn Morris <=
- [Emacs-diffs] Changes to emacs/doc/lispref/functions.texi,v, Richard M. Stallman, 2007/11/24
- [Emacs-diffs] Changes to emacs/doc/lispref/functions.texi,v, Juanma Barranquero, 2007/11/26
- [Emacs-diffs] Changes to emacs/doc/lispref/functions.texi,v, Glenn Morris, 2007/11/28
- [Emacs-diffs] Changes to emacs/doc/lispref/functions.texi,v, Glenn Morris, 2007/11/30
- [Emacs-diffs] Changes to emacs/doc/lispref/functions.texi,v, Glenn Morris, 2007/11/30