* Initial import:: First import of Gnulib modules.
* Modified imports:: Changing the import specification.
* Simple update:: Tracking Gnulib development.
-* CVS Issues:: Integration with CVS.
+* Source changes:: Impact of Gnulib on your source files.
+* VCS Issues:: Integration with Version Control Systems.
@end menu
File list:
lib/dummy.c
lib/strdup.c
- lib/string_.h
+ lib/string.in.h
m4/absolute-header.m4
m4/extensions.m4
m4/gnulib-common.m4
Creating directory ./m4
Copying file lib/dummy.c
Copying file lib/strdup.c
-Copying file lib/string_.h
+Copying file lib/string.in.h
Copying file m4/absolute-header.m4
Copying file m4/extensions.m4
Copying file m4/gnulib-common.m4
@example
...
-AM_CPPFLAGS = -I$(top_srcdir)/lib -I$(top_builddir)/lib
+AM_CPPFLAGS = -I$(top_builddir)/lib -I$(top_srcdir)/lib
...
LDADD = lib/libgnu.a
...
In the usual case where Autoconf is creating a @file{config.h} file,
you should include @file{config.h} first, before any other include
file. That way, for example, if @file{config.h} defines
-@samp{restrict} to be the empty string on a pre-C99 host, the
-definition is consistent for all include files.
-
-You should include Gnulib-provided headers before system headers,
-so that Gnulib-provided headers can adjust how a system header
-behaves.
-
-A final word of warning: Gnulib currently assumes it will be
-responsible for @emph{all} functions that end up in the Autoconf
-@code{@@LIBOBJS@@} variables (and/or @code{@@LTLIBOBJS@@} if using
-Libtool), e.g., those specified in @code{AC_REPLACE_FUNCS} in your
-@file{configure.ac}. Therefore, if you have any functions which are
-not covered by Gnulib which need that treatment, you have to
-essentially reimplement AC_REPLACE_FUNCS using different names; for an
-example, see the Findutils sources. Perhaps this will be improved in
-the future.
+@samp{restrict} to be the empty string on a pre-C99 host, or a macro
+like @samp{_FILE_OFFSET_BITS} that affects the layout of data
+structures, the definition is consistent for all include files.
+Also, on some platforms macros like @samp{_FILE_OFFSET_BITS} and
+@samp{_GNU_SOURCE} may be ineffective, or may have only a limited
+effect, if defined after the first system header file is included.
+
+Finally, note that you can not use @code{AC_LIBOBJ} or
+@code{AC_REPLACE_FUNCS} in your @file{configure.ac} and expect the
+resulting object files to be automatically added to @file{lib/libgnu.a}.
+This is because your @code{AC_LIBOBJ} and @code{AC_REPLACE_FUNCS} invocations
+from @file{configure.ac} augment a variable @code{@@LIBOBJS@@} (and/or
+@code{@@LTLIBOBJS@@} if using Libtool), whereas @file{lib/libgnu.a}
+is built from the contents of a different variable, usually
+@code{@@gl_LIBOBJS@@} (or @code{@@gl_LTLIBOBJS@@} if using Libtool).
@node Modified imports
@samp{--lib} command line argument.
@item gl_LGPL
-The presence of this macro corresponds to the @samp{--lgpl} command line
-argument. It takes no arguments.
+The presence of this macro without arguments corresponds to the @samp{--lgpl}
+command line argument. The presence of this macro with an argument (whose
+value must be 2 or 3) corresponds to the @samp{--lgpl=@var{arg}} command line
+argument.
@item gl_LIBTOOL
The presence of this macro corresponds to the @samp{--libtool} command line
file. Corresponds to the @samp{--macro-prefix} command line argument.
@end table
+
@node Simple update
@section Simple update
$ gnulib-tool --import
@end smallexample
+@noindent
This will create, update or remove files, as needed.
-@node CVS Issues
-@section CVS Issues
+Note: From time to time, changes are made in Gnulib that are not backward
+compatible. When updating to a more recent Gnulib, you should consult
+Gnulib's @file{NEWS} file to check whether the incompatible changes affect
+your project.
+
+
+@node Source changes
+@section Changing your sources for use with Gnulib
+
+Gnulib contains some header file overrides. This means that when building
+on systems with deficient header files in @file{/usr/include/}, it may create
+files named @file{string.h}, @file{stdlib.h}, @file{stdint.h} or similar in
+the build directory. In the other source directories of your package you
+will usually pass @samp{-I} options to the compiler, so that these Gnulib
+substitutes are visible and take precedence over the files in
+@file{/usr/include/}.
+
+These Gnulib substitute header files rely on @file{<config.h>} being
+already included. Furthermore @file{<config.h>} must be the first include
+in every compilation unit. This means that to @emph{all your source files}
+and likely also to @emph{all your tests source files} you need to add an
+@samp{#include <config.h>} at the top. Which source files are affected?
+Exactly those whose compilation includes a @samp{-I} option that refers to
+the Gnulib library directory.
+
+This is annoying, but inevitable: On many systems, @file{<config.h>} is
+used to set system dependent flags (such as @code{_GNU_SOURCE} on GNU systems),
+and these flags have no effect after any system header file has been included.
+
+
+@node VCS Issues
+@section Issues with Version Control Systems
+
+If a project stores its source files in a version control system (VCS),
+such as CVS, SVN, or Git, one needs to decide which files to commit.
All files created by @code{gnulib-tool}, except @file{gnulib-cache.m4},
should be treated like generated source files, like for example a
@file{parser.c} file is generated from @file{parser.y}.
+@itemize
+
+@item
In projects which commit all source files, whether generated or not, into
-CVS, the @code{gnulib-tool} generated files should all be committed.
+their VCS, the @code{gnulib-tool} generated files should all be committed.
+
+Gnulib also contains files generated by @command{make} (and removed by
+@code{make clean}), using information determined by @command{configure}
+They should not be checked into the VCS, but instead added to
+@file{.cvsignore}. When you have a Gnulib source file of the form
+@file{lib/foo_.h}, the corresponding @file{lib/foo.h} is such a file.
-In projects which customarily omit from the CVS all files that generated
+@item
+In projects which customarily omit from their VCS all files that are generated
from other source files, all these files and directories would not be
-added into CVS. The only file that must be added to CVS is
+added into the VCS. The only file that must be added to the VCS is
@file{gnulib-cache.m4} in the M4 macros directory. Also, the script for
-restoring files not in CVS, customarily called @file{autogen.sh} or
+restoring files not in the VCS, customarily called @file{autogen.sh} or
@file{bootstrap.sh}, will typically contain the statement for restoring
the omitted files:
but it does not offer the possibility to change the way Gnulib is used.
Also it does not report in the ChangeLogs the files that it had to add
because they were missing.
+
+@end itemize
projects / gnulib.git / blobdiff