| 1 | #serial 14
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| 2 | dnl Copyright (C) 2002, 2005, 2007, 2009-2011 Free Software Foundation, Inc.
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| 3 | dnl This file is free software; the Free Software Foundation
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| 4 | dnl gives unlimited permission to copy and/or distribute it,
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| 5 | dnl with or without modifications, as long as this notice is preserved.
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| 6 |
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| 7 | AC_DEFUN([gl_FUNC_DUP2],
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| 8 | [
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| 9 | AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
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| 10 | AC_REQUIRE([AC_CANONICAL_HOST])
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| 11 | m4_ifdef([gl_FUNC_DUP2_OBSOLETE], [
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| 12 | AC_CHECK_FUNCS_ONCE([dup2])
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| 13 | if test $ac_cv_func_dup2 = no; then
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| 14 | HAVE_DUP2=0
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| 15 | fi
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| 16 | ], [
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| 17 | AC_DEFINE([HAVE_DUP2], [1], [Define to 1 if you have the 'dup2' function.])
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| 18 | ])
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| 19 | if test $HAVE_DUP2 = 1; then
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| 20 | AC_CACHE_CHECK([whether dup2 works], [gl_cv_func_dup2_works],
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| 21 | [AC_RUN_IFELSE([
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| 22 | AC_LANG_PROGRAM([[#include <unistd.h>
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| 23 | #include <fcntl.h>
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| 24 | #include <errno.h>]],
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| 25 | [int result = 0;
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| 26 | #ifdef FD_CLOEXEC
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| 27 | if (fcntl (1, F_SETFD, FD_CLOEXEC) == -1)
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| 28 | result |= 1;
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| 29 | #endif
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| 30 | if (dup2 (1, 1) == 0)
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| 31 | result |= 2;
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| 32 | #ifdef FD_CLOEXEC
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| 33 | if (fcntl (1, F_GETFD) != FD_CLOEXEC)
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| 34 | result |= 4;
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| 35 | #endif
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| 36 | close (0);
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| 37 | if (dup2 (0, 0) != -1)
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| 38 | result |= 8;
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| 39 | /* Many gnulib modules require POSIX conformance of EBADF. */
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| 40 | if (dup2 (2, 1000000) == -1 && errno != EBADF)
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| 41 | result |= 16;
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| 42 | return result;
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| 43 | ])
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| 44 | ],
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| 45 | [gl_cv_func_dup2_works=yes], [gl_cv_func_dup2_works=no],
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| 46 | [case "$host_os" in
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| 47 | mingw*) # on this platform, dup2 always returns 0 for success
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| 48 | gl_cv_func_dup2_works=no;;
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| 49 | cygwin*) # on cygwin 1.5.x, dup2(1,1) returns 0
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| 50 | gl_cv_func_dup2_works=no;;
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| 51 | linux*) # On linux between 2008-07-27 and 2009-05-11, dup2 of a
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| 52 | # closed fd may yield -EBADF instead of -1 / errno=EBADF.
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| 53 | gl_cv_func_dup2_works=no;;
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| 54 | freebsd*) # on FreeBSD 6.1, dup2(1,1000000) gives EMFILE, not EBADF.
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| 55 | gl_cv_func_dup2_works=no;;
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| 56 | haiku*) # on Haiku alpha 2, dup2(1, 1) resets FD_CLOEXEC.
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| 57 | gl_cv_func_dup2_works=no;;
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| 58 | *) gl_cv_func_dup2_works=yes;;
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| 59 | esac])
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| 60 | ])
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| 61 | if test "$gl_cv_func_dup2_works" = no; then
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| 62 | REPLACE_DUP2=1
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| 63 | fi
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| 64 | fi
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| 65 | dnl Replace dup2() for supporting the gnulib-defined fchdir() function,
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| 66 | dnl to keep fchdir's bookkeeping up-to-date.
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| 67 | m4_ifdef([gl_FUNC_FCHDIR], [
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| 68 | gl_TEST_FCHDIR
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| 69 | if test $HAVE_FCHDIR = 0; then
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| 70 | REPLACE_DUP2=1
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| 71 | fi
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| 72 | ])
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| 73 | ])
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