| 1 | # link.m4 serial 11
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| 2 | dnl Copyright (C) 2009-2022 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_LINK],
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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]) dnl for cross-compiles
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| 11 | AC_CHECK_FUNCS_ONCE([link])
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| 12 | if test $ac_cv_func_link = no; then
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| 13 | HAVE_LINK=0
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| 14 | else
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| 15 | AC_CACHE_CHECK([whether link obeys POSIX],
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| 16 | [gl_cv_func_link_works],
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| 17 | [touch conftest.a
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| 18 | # Assume that if we have lstat, we can also check symlinks.
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| 19 | if test $ac_cv_func_lstat = yes; then
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| 20 | ln -s conftest.a conftest.lnk
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| 21 | fi
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| 22 | AC_RUN_IFELSE(
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| 23 | [AC_LANG_PROGRAM(
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| 24 | [[#include <unistd.h>
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| 25 | #include <stdio.h>
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| 26 | ]],
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| 27 | [[int result = 0;
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| 28 | if (!link ("conftest.a", "conftest.b/"))
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| 29 | result |= 1;
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| 30 | #if HAVE_LSTAT
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| 31 | if (!link ("conftest.lnk/", "conftest.b"))
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| 32 | result |= 2;
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| 33 | if (rename ("conftest.a", "conftest.b"))
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| 34 | result |= 4;
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| 35 | if (!link ("conftest.b", "conftest.lnk"))
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| 36 | result |= 8;
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| 37 | #endif
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| 38 | return result;
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| 39 | ]])],
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| 40 | [gl_cv_func_link_works=yes], [gl_cv_func_link_works=no],
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| 41 | [case "$host_os" in
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| 42 | # Guess yes on Linux systems.
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| 43 | linux-* | linux) gl_cv_func_link_works="guessing yes" ;;
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| 44 | # Guess yes on glibc systems.
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| 45 | *-gnu* | gnu*) gl_cv_func_link_works="guessing yes" ;;
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| 46 | # If we don't know, obey --enable-cross-guesses.
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| 47 | *) gl_cv_func_link_works="$gl_cross_guess_normal" ;;
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| 48 | esac
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| 49 | ])
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| 50 | rm -f conftest.a conftest.b conftest.lnk])
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| 51 | case "$gl_cv_func_link_works" in
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| 52 | *yes) ;;
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| 53 | *)
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| 54 | REPLACE_LINK=1
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| 55 | ;;
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| 56 | esac
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| 57 | fi
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| 58 | ])
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