84 lines
3 KiB
Plaintext
84 lines
3 KiB
Plaintext
# calloc.m4 serial 29
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# Copyright (C) 2004-2023 Free Software Foundation, Inc.
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# This file is free software; the Free Software Foundation
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# gives unlimited permission to copy and/or distribute it,
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# with or without modifications, as long as this notice is preserved.
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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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# _AC_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([_AC_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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[ac_cv_func_calloc_0_nonnull],
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[if test $cross_compiling != yes; then
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ac_cv_func_calloc_0_nonnull=yes
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AC_RUN_IFELSE(
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[AC_LANG_PROGRAM(
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[AC_INCLUDES_DEFAULT],
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[[int result = 0;
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char * volatile p = calloc (0, 0);
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if (!p)
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result |= 1;
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free (p);
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return result;
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]])],
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[],
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[ac_cv_func_calloc_0_nonnull=no])
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else
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case "$host_os" in
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# Guess yes on glibc systems.
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*-gnu* | gnu*) ac_cv_func_calloc_0_nonnull="guessing yes" ;;
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# Guess yes on musl systems.
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*-musl*) ac_cv_func_calloc_0_nonnull="guessing yes" ;;
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# Guess yes on native Windows.
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mingw*) ac_cv_func_calloc_0_nonnull="guessing yes" ;;
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# If we don't know, obey --enable-cross-guesses.
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*) ac_cv_func_calloc_0_nonnull="$gl_cross_guess_normal" ;;
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esac
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fi
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])
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AS_CASE([$ac_cv_func_calloc_0_nonnull], [*yes], [$1], [$2])
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])
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# gl_FUNC_CALLOC_GNU
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# ------------------
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# Replace calloc if it is not compatible with GNU libc.
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AC_DEFUN([gl_FUNC_CALLOC_GNU],
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[
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AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
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AC_REQUIRE([gl_FUNC_CALLOC_POSIX])
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REPLACE_CALLOC_FOR_CALLOC_GNU="$REPLACE_CALLOC_FOR_CALLOC_POSIX"
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if test $REPLACE_CALLOC_FOR_CALLOC_GNU = 0; then
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_AC_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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if test $REPLACE_MALLOC_FOR_MALLOC_POSIX = 1; then
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REPLACE_CALLOC_FOR_CALLOC_POSIX=1
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fi
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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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