74 lines
2.7 KiB
Plaintext
74 lines
2.7 KiB
Plaintext
# ungetc.m4 serial 10
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dnl Copyright (C) 2009-2023 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_ONCE([gl_FUNC_UNGETC_WORKS],
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[
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AC_REQUIRE([AC_PROG_CC])
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AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
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AC_CACHE_CHECK([whether ungetc works on arbitrary bytes],
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[gl_cv_func_ungetc_works],
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[AC_RUN_IFELSE([AC_LANG_PROGRAM([[
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#include <stdio.h>
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]], [[FILE *f;
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if (!(f = fopen ("conftest.tmp", "w+")))
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return 1;
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if (fputs ("abc", f) < 0)
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{ fclose (f); return 2; }
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rewind (f);
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if (fgetc (f) != 'a')
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{ fclose (f); return 3; }
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if (fgetc (f) != 'b')
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{ fclose (f); return 4; }
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if (ungetc ('d', f) != 'd')
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{ fclose (f); return 5; }
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if (ftell (f) != 1)
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{ fclose (f); return 6; }
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if (fgetc (f) != 'd')
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{ fclose (f); return 7; }
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if (ftell (f) != 2)
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{ fclose (f); return 8; }
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if (fseek (f, 0, SEEK_CUR) != 0)
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{ fclose (f); return 9; }
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if (ftell (f) != 2)
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{ fclose (f); return 10; }
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if (fgetc (f) != 'c')
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{ fclose (f); return 11; }
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fclose (f);
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remove ("conftest.tmp");
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]])],
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[gl_cv_func_ungetc_works=yes], [gl_cv_func_ungetc_works=no],
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[case "$host_os" in
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# Guess yes on glibc systems.
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*-gnu* | gnu*) gl_cv_func_ungetc_works="guessing yes" ;;
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# Guess yes on musl systems.
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*-musl*) gl_cv_func_ungetc_works="guessing yes" ;;
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# Guess yes on bionic systems.
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*-android*) gl_cv_func_ungetc_works="guessing yes" ;;
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# Guess yes on native Windows.
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mingw*) gl_cv_func_ungetc_works="guessing yes" ;;
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# If we don't know, obey --enable-cross-guesses.
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*) gl_cv_func_ungetc_works="$gl_cross_guess_normal" ;;
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esac
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])
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])
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gl_ftello_broken_after_ungetc=no
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case "$gl_cv_func_ungetc_works" in
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*yes) ;;
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*)
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dnl On macOS >= 10.15, where the above program fails with exit code 6,
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dnl we fix it through an ftello override.
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case "$host_os" in
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darwin*) gl_ftello_broken_after_ungetc=yes ;;
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*)
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AC_DEFINE([FUNC_UNGETC_BROKEN], [1],
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[Define to 1 if ungetc is broken when used on arbitrary bytes.])
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;;
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esac
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;;
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esac
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])
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