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Diffstat (limited to '')
| -rw-r--r-- | m4/semaphore.m4 | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/m4/semaphore.m4 b/m4/semaphore.m4 new file mode 100644 index 0000000..edbed96 --- /dev/null +++ b/m4/semaphore.m4 @@ -0,0 +1,45 @@ +# semaphore.m4 serial 1 +dnl Copyright (C) 2019-2023 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. + +# Sets LIB_SEMAPHORE to the library needed, in addition to $(LIBMULTITHREAD), +# for getting the <semaphore.h> functions. + +AC_DEFUN([gl_SEMAPHORE], +[ + AC_REQUIRE([gl_THREADLIB]) + dnl sem_post is + dnl - in libc on macOS, FreeBSD, AIX, IRIX, Solaris 11, Haiku, Cygwin, + dnl - in libpthread on glibc systems, OpenBSD, + dnl - in libpthread or librt on NetBSD, + dnl - in librt on HP-UX 11, OSF/1, Solaris 10. + dnl On the platforms where -lpthread is needed, it is contained in + dnl $LIBMULTITHREAD. Therefore, the only library we need to test for is -lrt. + AC_CACHE_CHECK([for library needed for semaphore functions], + [gl_cv_semaphore_lib], + [save_LIBS="$LIBS" + LIBS="$LIBS $LIBMULTITHREAD" + AC_LINK_IFELSE( + [AC_LANG_PROGRAM( + [[#include <semaphore.h>]], + [[sem_post ((sem_t *)0);]])], + [gl_cv_semaphore_lib=none], + [LIBS="$LIBS -lrt" + AC_LINK_IFELSE( + [AC_LANG_PROGRAM( + [[#include <semaphore.h>]], + [[sem_post ((sem_t *)0);]])], + [gl_cv_semaphore_lib='-lrt'], + [gl_cv_semaphore_lib=none]) + ]) + LIBS="$save_LIBS" + ]) + if test "x$gl_cv_semaphore_lib" = xnone; then + LIB_SEMAPHORE= + else + LIB_SEMAPHORE="$gl_cv_semaphore_lib" + fi + AC_SUBST([LIB_SEMAPHORE]) +]) |