\input texinfo @c -*-texinfo-*-
-@comment $Id: gnulib.texi,v 1.10 2005-06-27 22:36:50 jas Exp $
+@comment $Id: gnulib.texi,v 1.15 2005-07-30 13:47:19 karl Exp $
@comment %**start of header
@setfilename gnulib.info
@settitle GNU Gnulib
@syncodeindex pg cp
@comment %**end of header
-@set UPDATED $Date: 2005-06-27 22:36:50 $
+@set UPDATED $Date: 2005-07-30 13:47:19 $
@copying
This manual is for GNU Gnulib (updated @value{UPDATED}),
@chapter Gnulib
This manual contains some bare-bones documentation, but not much more.
-It's mostly been a place to store notes until someone (you?) gets
+It's mostly been a place to store notes until someone (you?)@ gets
around to writing a coherent manual.
Getting started:
@menu
* Comments::
* Header files::
+* Quoting::
* ctime::
* inet_ntoa::
* Out of memory handling::
* Library version handling::
+* Regular expressions::
@end menu
+
@node Comments
@section Comments
your header file as something available for C programs only, or for C
and C++ programs alike.
-@subsection Include ordering
+@subheading Include ordering
When writing a gnulib module, or even in general, a good way to order
the @samp{#include} directives is the following.
arbitrary order.
@end itemize
+
+@node Quoting
+@section Quoting
+
+@cindex Quoting
+@findex quote
+@findex quotearg
+
+Gnulib provides @samp{quote} and @samp{quotearg} modules to help with
+quoting text, such as file names, in messages to the user. Here's an
+example of using @samp{quote}:
+
+@example
+#include <quote.h>
+ ...
+ error (0, errno, _("cannot change owner of %s"), quote (fname));
+@end example
+
+This differs from
+
+@example
+ error (0, errno, _("cannot change owner of `%s'"), fname);
+@end example
+
+@noindent in that @code{quote} escapes unusual characters in
+@code{fname}, e.g., @samp{'} and control characters like @samp{\n}.
+
+@findex quote_n
+However, a caveat: @code{quote} reuses the storage that it returns.
+Hence if you need more than one thing quoted at the same time, you
+need to use @code{quote_n}.
+
+@findex quotearg_alloc
+Also, the quote module is not suited for multithreaded applications.
+In that case, you have to use @code{quotearg_alloc}, defined in the
+@samp{quotearg} module, which is decidedly less convenient.
+
+
@node ctime
@section ctime
@findex ctime
@node Library version handling
@section Library version handling
-The module ``check_version'' can be useful when your gnulib
+The module @samp{check-version} can be useful when your gnulib
application is a system library. You will typically wrap the call to
the @code{check_version} function through a library API, your library
header file may contain:
extern const char *stringprep_check_version (const char *req_version);
@end example
-The implementation of @code{stringprep_check_version} would simply
-pass on the call to @code{check_version}.
+To avoid ELF symbol collisions with other libraries that use the
+@samp{check-version} module, add to @file{config.h} through a
+AC_DEFINE something like:
+
+@example
+AC_DEFINE(check_version, stringprep_check_version, [Rename check_version.])
+@end example
+
+The @code{stringprep_check_version} function will thus be implemented
+by the @code{check_version} module.
There are two uses of the interface. The first is a way to provide
for applications to find out the version number of the library it
die ("version mismatch\n");
@end example
+
+@node Regular expressions
+@section Regular expressions
+
+Gnulib supports many different types of regular expressions; although
+the underlying features are the same or identical, the syntax used
+varies. The descriptions given here for the different types are
+generated automatically.
+
+@include regexprops-generic.texi
+
+
@node Invoking gnulib-tool
@chapter Invoking gnulib-tool
...
@end example
+@code{gl_INIT} will in turn call the macros related with the
+gnulib functions, be it specific gnulib macros, like @code{gl_FUNC_ALLOCA}
+or autoconf or automake macro like @code{AC_FUNC_ALLOCA} or
+@code{AM_FUNC_GETLINE} so there is no need to call those macros yourself
+when you use the corresponding gnulib modules.
+
You must also make sure that the gnulib library is built. Add the
@code{Makefile} in the gnulib source base directory to
@code{AC_CONFIG_FILES}, as in:
@end example
Finally, you have to add compiler and linker flags in the appropriate
-source directories, so that you can make use
-of the gnulib library. For example:
+source directories, so that you can make use of the gnulib library.
+Since some modules (@samp{getopt}, for example) may copy files into
+the build directory, @file{top_builddir/lib} is needed as well
+as @file{top_srcdir/lib}. For example:
@example
...
-AM_CPPFLAGS = -I$(top_srcdir)/lib
+AM_CPPFLAGS = -I$(top_srcdir)/lib -I$(top_builddir)/lib
...
LIBADD = lib/libgnu.a
...
@end example
Don't forget to @code{#include} the various header files. In this
-example, you would need to make sure that @samp{#include <strdup.h>}
+example, you would need to make sure that @samp{#include "strdup.h"}
is evaluated when compiling all source code files, that want to make
-use of @code{strdup}.
-
+use of @code{strdup}.
+
+When an include file is provided by the gnulib
+you shouldn't try to include the corresponding system header files
+yourself but let the gnulib header file do it as the ordering
+of the definition for some symbols may be significant.
+
+For example, to use the @code{time_r} gnulib module you should
+use include header file provided by the gnulib, and so
+@samp{#include "time_r.h"}, but you shouldn't explicitely
+@samp{#include <time.h>} as it is already done in @file{time_r.h}
+before the redefinition of some symbols.
@node Importing updated files
@section Importing updated files
projects / gnulib.git / blobdiff