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37 lines
1.2 KiB
Plaintext
37 lines
1.2 KiB
Plaintext
# copy-file-range.m4
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dnl Copyright 2019-2020 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_COPY_FILE_RANGE],
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[
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AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
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dnl Persuade glibc <unistd.h> to declare copy_file_range.
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AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
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dnl Use AC_LINK_IFELSE, rather than AC_CHECK_FUNCS or a variant,
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dnl since we don't want AC_CHECK_FUNCS's checks for glibc stubs.
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dnl Programs that use copy_file_range must fall back on read+write
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dnl anyway, and there's little point to substituting the Gnulib stub
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dnl for a glibc stub.
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AC_CACHE_CHECK([for copy_file_range], [gl_cv_func_copy_file_range],
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[AC_LINK_IFELSE(
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[AC_LANG_PROGRAM(
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[[#include <unistd.h>
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]],
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[[ssize_t (*func) (int, off_t *, int, off_t, size_t, unsigned)
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= copy_file_range;
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return func (0, 0, 0, 0, 0, 0) & 127;
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]])
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],
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[gl_cv_func_copy_file_range=yes],
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[gl_cv_func_copy_file_range=no])
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])
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if test "$gl_cv_func_copy_file_range" != yes; then
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HAVE_COPY_FILE_RANGE=0
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fi
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])
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