Simon Josefsson wrote on 2005-12-17: > The sys_socket module below will create a sys/socket.h file, primarily > for mingw32, but it could be extended for other systems or missing > sys/socket.h features in the future. > > This would solve the problem of accessing sys/socket.h stuff in > applications.
I like this idea. So we can get rid of #if HAVE_SYS_SOCKET_H in many places. > Index: lib/socket_.h > =================================================================== > RCS file: lib/socket_.h > diff -N lib/socket_.h > --- /dev/null 1 Jan 1970 00:00:00 -0000 > +++ lib/socket_.h 16 Dec 2005 15:04:41 -0000 > @@ -0,0 +1,26 @@ > +/* Provide a sys/socket header file for systems lacking it (read: mingw32). > + Copyright (C) 2005 Free Software Foundation, Inc. > + Written by Simon Josefsson. > + > + This program is free software; you can redistribute it and/or modify > + it under the terms of the GNU General Public License as published by > + the Free Software Foundation; either version 2, or (at your option) > + any later version. > + > + This program is distributed in the hope that it will be useful, > + but WITHOUT ANY WARRANTY; without even the implied warranty of > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + GNU General Public License for more details. > + > + You should have received a copy of the GNU General Public License > + along with this program; if not, write to the Free Software Foundation, > + Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ > + > +#ifndef _SYS_SOCKET_H > +#define _SYS_SOCKET_H > + > +#if HAVE_WINSOCK2_H > +# include <winsock2.h> > +#endif Comments should indicate for which platforms this file is meant to be useful and on which platforms you expect <winsock2.h> to be present. (Currently only mingw, I think?) Also, this should include <ws2tcpip.h>, so that socklen_t is defined (and a type redefinition error is avoided when the user includes <ws2tcpip.h>). > + > +#endif /* _SYS_SOCKET_H */ > Index: m4/sys_socket_h.m4 > =================================================================== > RCS file: m4/sys_socket_h.m4 > diff -N m4/sys_socket_h.m4 > --- /dev/null 1 Jan 1970 00:00:00 -0000 > +++ m4/sys_socket_h.m4 16 Dec 2005 15:04:41 -0000 > @@ -0,0 +1,19 @@ > +# sys_socket_h.m4 serial 1 > +dnl Copyright (C) 2005 Free Software Foundation, Inc. > +dnl This file is free software; the Free Software Foundation > +dnl gives unlimited permission to copy and/or distribute it, > +dnl with or without modifications, as long as this notice is preserved. > + > +dnl From Simon Josefsson. > + > +AC_DEFUN([gl_HEADER_SYS_SOCKET], > +[ > + AC_CHECK_HEADERS_ONCE([sys/socket.h]) > + if test $ac_cv_header_sys_socket_h = yes; then > + SYS_SOCKET_H='' > + else > + AC_CHECK_HEADERS_ONCE([winsock2.h]) > + SYS_SOCKET_H='sys/socket.h' > + fi > + AC_SUBST(SYS_SOCKET_H) > +]) Looks good. Fine. > Index: modules/sys_socket > =================================================================== > RCS file: modules/sys_socket > diff -N modules/sys_socket > --- /dev/null 1 Jan 1970 00:00:00 -0000 > +++ modules/sys_socket 16 Dec 2005 15:04:41 -0000 > @@ -0,0 +1,36 @@ > +Description: > +A <sys/socket.h> for systems lacking it. > +(Currently only useful for mingw32, it will simply include winsock2.h.) > + > +Files: > +lib/socket_.h > +m4/sys_socket_h.m4 > + > +Depends-on: > + > +configure.ac: > +gl_HEADER_SYS_SOCKET > + > +Makefile.am: > +BUILT_SOURCES += $(SYS_SOCKET_H) > +EXTRA_DIST += socket_.h > + > +# We need the following in order to create <sys/socket.h> when the system > +# doesn't have one that works with the given compiler. > +sys/socket.h: socket_.h > + mkdir sys Create the directory only when it does not exist. (Otherwise the user is blocked if he happens to press Ctrl-C after the sys directory has been created but before sys/socket.h is present.) > + cp $(srcdir)/socket_.h [EMAIL PROTECTED] > + mv [EMAIL PROTECTED] $@ > +MOSTLYCLEANFILES += sys/socket.h sys/socket.h-t > + > +mostlylocal-clean: Should be mostlyclean-local, not mostlylocal-clean. > + rmdir sys Remove the directory only when it exists and is empty. (Some systems create files in your directories without being asked for, e.g. .DS_Store on MacOS X.) > + > +Include: > +#include <sys/socket.h> > + > +License: > +LGPL > + > +Maintainer: > +Simon Josefsson OK, good. > However, it does not solve the problem of accessing sys/socket.h > inside autoconf tests, and in particular from the socklen > module. > > Currently the socklen test fail on mingw32: > > checking for socklen_t... no > checking for socklen_t equivalent... > configure: error: Cannot find a type to use in place of socklen_t > > because: > > configure:3814: i586-mingw32msvc-gcc -c -g -O2 conftest.c >&5 > conftest.c:23:26: sys/socket.h: No such file or directory > > I can think of three solutions: > > 0) In socklen, default the type to 'int' instead of aborting. This > would be compatible with mingw32, they use 'typedef int socklen_t'. > The patch below implement this. > > 1) Fix the socklen M4 test to check for the existence of socket.h, > winsock2.h and ws2tcpip.h and include the appropriate headers when > needed. This has the problem that the application will have to > include the non-POSIX headers too, if they need socklen_t. The > patch below implement this. > > 2) Create the gnulib sys/socket.h directly in the M4 macro, and set up > CFLAGS to include the gnulib directory during ./configure. This > has the problem that all modules invoked before the sys_socket > module will not work. It seem wrong for those modules to depend on > "sys_socket", because sys/socket.h is a POSIX header which most > tests could assume. A fourth solution is 3) Set some configure variables during sys_socket_h.m4 that are used in the socklen.m4 tests. Ad 0): I don't like this, because socklen_t values are passed through a pointer, and if the argument type of getpeername() is not 'int *', the program will break horribly. Don't make the autoconf test less reliable than it is now. Ad 1): Having socklen.m4 check for ws2tcpip.h is probably unavoidable, since it is this header file which defines socklen_t on mingw, and winsock2.h doesn't. But let the sys_socket_h module do the rest, and let user programs use only <sys/socket.h>. I don't like the two gnulib modules be so tied together, but can't see a better solution. Ad 2): Creating a file directly from within an m4 macro looks wrong. Reasons: - Filenames don't belong in .m4 files. - The removal of the file must be triggered by "make distclean", i.e. from a Makefile. Then it's more symmetrical if the file is created by the same Makefile. > I think 0 and 1 should be done, together with installing the > sys_socket module. I think a mix of 1) and 3) is the best. > Possibly, socklen should not test for ws2tcpip.h. I think it needs to. Bruno _______________________________________________ bug-gnulib mailing list bug-gnulib@gnu.org http://lists.gnu.org/mailman/listinfo/bug-gnulib
