diff options
Diffstat (limited to 'm4/fcntl.m4')
| -rw-r--r-- | m4/fcntl.m4 | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/m4/fcntl.m4 b/m4/fcntl.m4 new file mode 100644 index 0000000000..f361b7d578 --- /dev/null +++ b/m4/fcntl.m4 @@ -0,0 +1,49 @@ +# fcntl.m4 serial 1 +dnl Copyright (C) 2009 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. + +# For now, this module ensures that fcntl() +# - supports or emulates F_DUPFD_CLOEXEC +# Still to be ported to various platforms: +# - supports F_DUPFD correctly +# Still to be ported to mingw: +# - F_GETFD, F_SETFD, F_DUPFD +# - F_DUPFD_CLOEXEC +# - F_GETFL, F_SETFL +# - F_GETOWN, F_SETOWN +# - F_GETLK, F_SETLK, F_SETLKW +AC_DEFUN([gl_FUNC_FCNTL], +[ + dnl Persuade glibc to expose F_DUPFD_CLOEXEC. + AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS]) + AC_REQUIRE([gl_FCNTL_H_DEFAULTS]) + AC_CHECK_FUNCS_ONCE([fcntl]) + if test $ac_cv_func_fcntl = no; then + HAVE_FCNTL=0 + else + AC_CACHE_CHECK([whether fcntl understands F_DUPFD_CLOEXEC], + [gl_cv_func_fcntl_f_dupfd_cloexec], + [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[ +#include <fcntl.h> +#ifndef F_DUPFD_CLOEXEC +choke me +#endif + ]])], + [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[ +#ifdef __linux__ +/* The Linux kernel only added F_DUPFD_CLOEXEC in 2.6.24, so we always replace + it to support the semantics on older kernels that failed with EINVAL. */ +choke me +#endif + ]])], + [gl_cv_func_fcntl_f_dupfd_cloexec=yes], + [gl_cv_func_fcntl_f_dupfd_cloexec="needs runtime check"])], + [gl_cv_func_fcntl_f_dupfd_cloexec=no])]) + if test "$gl_cv_func_fcntl_f_dupfd_cloexec" != yes; then + REPLACE_FCNTL=1 + AC_LIBOBJ([fcntl]) + fi + fi +]) |