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3dac6181c1
Should fix fport_input_waiting when neither poll nor select nor FIONREAD are available, which is the case on MinGW. Thanks to Eli Zaretskii for the report.
84 lines
2.8 KiB
Text
84 lines
2.8 KiB
Text
#serial 19
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dnl Copyright (C) 2002, 2005, 2007, 2009-2013 Free Software Foundation, Inc.
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dnl This file is free software; the Free Software Foundation
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dnl gives unlimited permission to copy and/or distribute it,
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dnl with or without modifications, as long as this notice is preserved.
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AC_DEFUN([gl_FUNC_DUP2],
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[
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AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
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AC_REQUIRE([AC_CANONICAL_HOST])
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m4_ifdef([gl_FUNC_DUP2_OBSOLETE], [
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AC_CHECK_FUNCS_ONCE([dup2])
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if test $ac_cv_func_dup2 = no; then
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HAVE_DUP2=0
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fi
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], [
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AC_DEFINE([HAVE_DUP2], [1], [Define to 1 if you have the 'dup2' function.])
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])
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if test $HAVE_DUP2 = 1; then
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AC_CACHE_CHECK([whether dup2 works], [gl_cv_func_dup2_works],
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[AC_RUN_IFELSE([
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AC_LANG_PROGRAM([[#include <unistd.h>
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#include <fcntl.h>
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#include <errno.h>]],
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[int result = 0;
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#ifdef FD_CLOEXEC
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if (fcntl (1, F_SETFD, FD_CLOEXEC) == -1)
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result |= 1;
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#endif
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if (dup2 (1, 1) == 0)
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result |= 2;
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#ifdef FD_CLOEXEC
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if (fcntl (1, F_GETFD) != FD_CLOEXEC)
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result |= 4;
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#endif
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close (0);
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if (dup2 (0, 0) != -1)
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result |= 8;
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/* Many gnulib modules require POSIX conformance of EBADF. */
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if (dup2 (2, 1000000) == -1 && errno != EBADF)
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result |= 16;
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/* Flush out a cygwin core dump. */
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if (dup2 (2, -1) != -1 || errno != EBADF)
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result |= 32;
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return result;
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])
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],
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[gl_cv_func_dup2_works=yes], [gl_cv_func_dup2_works=no],
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[case "$host_os" in
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mingw*) # on this platform, dup2 always returns 0 for success
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gl_cv_func_dup2_works="guessing no" ;;
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cygwin*) # on cygwin 1.5.x, dup2(1,1) returns 0
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gl_cv_func_dup2_works="guessing no" ;;
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linux*) # On linux between 2008-07-27 and 2009-05-11, dup2 of a
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# closed fd may yield -EBADF instead of -1 / errno=EBADF.
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gl_cv_func_dup2_works="guessing no" ;;
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freebsd*) # on FreeBSD 6.1, dup2(1,1000000) gives EMFILE, not EBADF.
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gl_cv_func_dup2_works="guessing no" ;;
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haiku*) # on Haiku alpha 2, dup2(1, 1) resets FD_CLOEXEC.
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gl_cv_func_dup2_works="guessing no" ;;
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*) gl_cv_func_dup2_works="guessing yes" ;;
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esac])
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])
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case "$gl_cv_func_dup2_works" in
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*yes) ;;
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*)
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REPLACE_DUP2=1
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;;
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esac
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fi
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dnl Replace dup2() for supporting the gnulib-defined fchdir() function,
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dnl to keep fchdir's bookkeeping up-to-date.
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m4_ifdef([gl_FUNC_FCHDIR], [
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gl_TEST_FCHDIR
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if test $HAVE_FCHDIR = 0; then
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if test $HAVE_DUP2 = 1; then
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REPLACE_DUP2=1
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fi
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fi
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])
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])
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# Prerequisites of lib/dup2.c.
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AC_DEFUN([gl_PREREQ_DUP2], [])
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