HCoop / bpt / emacs.git / blame
| Commit | Line | Data |
|---|---|---|
| 067428c1 PE |
1 | # fcntl.m4 serial 5 |
| 2 | dnl Copyright (C) 2009-2013 Free Software Foundation, Inc. | |
| 3 | dnl This file is free software; the Free Software Foundation | |
| 4 | dnl gives unlimited permission to copy and/or distribute it, | |
| 5 | dnl with or without modifications, as long as this notice is preserved. | |
| 6 | ||
| 7 | # For now, this module ensures that fcntl() | |
| 8 | # - supports F_DUPFD correctly | |
| 9 | # - supports or emulates F_DUPFD_CLOEXEC | |
| 10 | # - supports F_GETFD | |
| 11 | # Still to be ported to mingw: | |
| 12 | # - F_SETFD | |
| 13 | # - F_GETFL, F_SETFL | |
| 14 | # - F_GETOWN, F_SETOWN | |
| 15 | # - F_GETLK, F_SETLK, F_SETLKW | |
| 16 | AC_DEFUN([gl_FUNC_FCNTL], | |
| 17 | [ | |
| 18 | dnl Persuade glibc to expose F_DUPFD_CLOEXEC. | |
| 19 | AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS]) | |
| 20 | AC_REQUIRE([gl_FCNTL_H_DEFAULTS]) | |
| 21 | AC_REQUIRE([AC_CANONICAL_HOST]) | |
| 22 | AC_CHECK_FUNCS_ONCE([fcntl]) | |
| 23 | if test $ac_cv_func_fcntl = no; then | |
| 24 | gl_REPLACE_FCNTL | |
| 25 | else | |
| 26 | dnl cygwin 1.5.x F_DUPFD has wrong errno, and allows negative target | |
| 27 | dnl haiku alpha 2 F_DUPFD has wrong errno | |
| 28 | AC_CACHE_CHECK([whether fcntl handles F_DUPFD correctly], | |
| 29 | [gl_cv_func_fcntl_f_dupfd_works], | |
| 30 | [AC_RUN_IFELSE([AC_LANG_PROGRAM([[ | |
| 31 | #include <fcntl.h> | |
| 32 | #include <errno.h> | |
| 33 | ]], [[int result = 0; | |
| 34 | if (fcntl (0, F_DUPFD, -1) != -1) result |= 1; | |
| 35 | if (errno != EINVAL) result |= 2; | |
| 36 | return result; | |
| 37 | ]])], | |
| 38 | [gl_cv_func_fcntl_f_dupfd_works=yes], | |
| 39 | [gl_cv_func_fcntl_f_dupfd_works=no], | |
| 40 | [# Guess that it works on glibc systems | |
| 41 | case $host_os in #(( | |
| 42 | *-gnu*) gl_cv_func_fcntl_f_dupfd_works="guessing yes";; | |
| 43 | *) gl_cv_func_fcntl_f_dupfd_works="guessing no";; | |
| 44 | esac])]) | |
| 45 | case $gl_cv_func_fcntl_f_dupfd_works in | |
| 46 | *yes) ;; | |
| 47 | *) gl_REPLACE_FCNTL | |
| 48 | AC_DEFINE([FCNTL_DUPFD_BUGGY], [1], [Define this to 1 if F_DUPFD | |
| 49 | behavior does not match POSIX]) ;; | |
| 50 | esac | |
| 51 | ||
| 52 | dnl Many systems lack F_DUPFD_CLOEXEC | |
| 53 | AC_CACHE_CHECK([whether fcntl understands F_DUPFD_CLOEXEC], | |
| 54 | [gl_cv_func_fcntl_f_dupfd_cloexec], | |
| 55 | [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[ | |
| 56 | #include <fcntl.h> | |
| 57 | #ifndef F_DUPFD_CLOEXEC | |
| 58 | choke me | |
| 59 | #endif | |
| 60 | ]])], | |
| 61 | [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[ | |
| 62 | #ifdef __linux__ | |
| 63 | /* The Linux kernel only added F_DUPFD_CLOEXEC in 2.6.24, so we always replace | |
| 64 | it to support the semantics on older kernels that failed with EINVAL. */ | |
| 65 | choke me | |
| 66 | #endif | |
| 67 | ]])], | |
| 68 | [gl_cv_func_fcntl_f_dupfd_cloexec=yes], | |
| 69 | [gl_cv_func_fcntl_f_dupfd_cloexec="needs runtime check"])], | |
| 70 | [gl_cv_func_fcntl_f_dupfd_cloexec=no])]) | |
| 71 | if test "$gl_cv_func_fcntl_f_dupfd_cloexec" != yes; then | |
| 72 | gl_REPLACE_FCNTL | |
| 73 | dnl No witness macro needed for this bug. | |
| 74 | fi | |
| 75 | fi | |
| 76 | dnl Replace fcntl() for supporting the gnulib-defined fchdir() function, | |
| 77 | dnl to keep fchdir's bookkeeping up-to-date. | |
| 78 | m4_ifdef([gl_FUNC_FCHDIR], [ | |
| 79 | gl_TEST_FCHDIR | |
| 80 | if test $HAVE_FCHDIR = 0; then | |
| 81 | gl_REPLACE_FCNTL | |
| 82 | fi | |
| 83 | ]) | |
| 84 | ]) | |
| 85 | ||
| 86 | AC_DEFUN([gl_REPLACE_FCNTL], | |
| 87 | [ | |
| 88 | AC_REQUIRE([gl_FCNTL_H_DEFAULTS]) | |
| 89 | AC_CHECK_FUNCS_ONCE([fcntl]) | |
| 90 | if test $ac_cv_func_fcntl = no; then | |
| 91 | HAVE_FCNTL=0 | |
| 92 | else | |
| 93 | REPLACE_FCNTL=1 | |
| 94 | fi | |
| 95 | ]) |