80 lines
3.2 KiB
Text
80 lines
3.2 KiB
Text
# calloc.m4
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# serial 36
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dnl Copyright (C) 2004-2025 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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dnl This file is offered as-is, without any warranty.
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# Written by Jim Meyering.
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# Determine whether calloc (N, S) returns non-NULL when N*S is zero,
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# and returns NULL when N*S overflows.
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# If so, define HAVE_CALLOC. Otherwise, define calloc to rpl_calloc
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# and arrange to use a calloc wrapper function that does work in that case.
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# gl_FUNC_CALLOC_IF([IF-WORKS], [IF-NOT])
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# ---------------------------------------
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# If calloc is compatible with GNU calloc, run IF-WORKS, otherwise, IF-NOT.
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AC_DEFUN([gl_FUNC_CALLOC_IF],
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[
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AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
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AC_CACHE_CHECK([whether calloc (0, n) and calloc (n, 0) return nonnull],
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[gl_cv_func_calloc_0_nonnull],
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[AC_RUN_IFELSE(
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[AC_LANG_PROGRAM(
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[[#include <stdlib.h>
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/* Use pcalloc to test; "volatile" prevents the compiler
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from optimizing the calloc call away. */
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void *(*volatile pcalloc) (size_t, size_t) = calloc;]],
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[[void *p = pcalloc (0, 0);
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int result = !p;
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free (p);
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return result;]])],
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[gl_cv_func_calloc_0_nonnull=yes],
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[gl_cv_func_calloc_0_nonnull=no],
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[AS_CASE([$host_os],
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[# Guess yes on platforms where we know the result.
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*-gnu* | freebsd* | netbsd* | openbsd* | bitrig* \
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| gnu* | *-musl* | midipix* | midnightbsd* \
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| hpux* | solaris* | cygwin* | mingw* | windows* | msys*],
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[gl_cv_func_calloc_0_nonnull="guessing yes"],
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[# If we don't know, obey --enable-cross-guesses.
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gl_cv_func_calloc_0_nonnull="$gl_cross_guess_normal"])])])
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AS_CASE([$gl_cv_func_calloc_0_nonnull], [*yes], [$1], [$2])
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])
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# gl_FUNC_CALLOC_GNU
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# ------------------
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# Replace calloc if it is not compatible with GNU libc.
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AC_DEFUN([gl_FUNC_CALLOC_GNU],
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[
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AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
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AC_REQUIRE([gl_FUNC_CALLOC_POSIX])
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dnl Through the dependency on module extensions-aix, _LINUX_SOURCE_COMPAT
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dnl gets defined already before this macro gets invoked. This helps
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dnl if !(__VEC__ || __AIXVEC), and doesn't hurt otherwise.
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REPLACE_CALLOC_FOR_CALLOC_GNU="$REPLACE_CALLOC_FOR_CALLOC_POSIX"
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if test $REPLACE_CALLOC_FOR_CALLOC_GNU = 0; then
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gl_FUNC_CALLOC_IF([], [REPLACE_CALLOC_FOR_CALLOC_GNU=1])
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fi
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])# gl_FUNC_CALLOC_GNU
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# gl_FUNC_CALLOC_POSIX
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# --------------------
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# Test whether 'calloc' is POSIX compliant (sets errno to ENOMEM when it
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# fails, and doesn't mess up with ptrdiff_t or size_t overflow),
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# and replace calloc if it is not.
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AC_DEFUN([gl_FUNC_CALLOC_POSIX],
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[
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AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
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AC_REQUIRE([gl_FUNC_MALLOC_POSIX])
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REPLACE_CALLOC_FOR_CALLOC_POSIX=$REPLACE_MALLOC_FOR_MALLOC_POSIX
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dnl Although in theory we should also test for size_t overflow,
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dnl in practice testing for ptrdiff_t overflow suffices
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dnl since PTRDIFF_MAX <= SIZE_MAX on all known Gnulib porting targets.
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dnl A separate size_t test would slow down 'configure'.
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])
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