| 1 | # calloc.m4 serial 27
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| 2 |
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| 3 | # Copyright (C) 2004-2021 Free Software Foundation, Inc.
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| 4 | # This file is free software; the Free Software Foundation
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| 5 | # gives unlimited permission to copy and/or distribute it,
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| 6 | # with or without modifications, as long as this notice is preserved.
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| 7 |
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| 8 | # Written by Jim Meyering.
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| 9 |
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| 10 | # Determine whether calloc (N, S) returns non-NULL when N*S is zero,
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| 11 | # and returns NULL when N*S overflows.
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| 12 | # If so, define HAVE_CALLOC. Otherwise, define calloc to rpl_calloc
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| 13 | # and arrange to use a calloc wrapper function that does work in that case.
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| 14 |
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| 15 | # _AC_FUNC_CALLOC_IF([IF-WORKS], [IF-NOT])
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| 16 | # -------------------------------------
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| 17 | # If calloc is compatible with GNU calloc, run IF-WORKS, otherwise, IF-NOT.
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| 18 | AC_DEFUN([_AC_FUNC_CALLOC_IF],
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| 19 | [
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| 20 | AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
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| 21 | AC_CACHE_CHECK([whether calloc (0, n) and calloc (n, 0) return nonnull],
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| 22 | [ac_cv_func_calloc_0_nonnull],
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| 23 | [if test $cross_compiling != yes; then
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| 24 | ac_cv_func_calloc_0_nonnull=yes
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| 25 | AC_RUN_IFELSE(
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| 26 | [AC_LANG_PROGRAM(
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| 27 | [AC_INCLUDES_DEFAULT],
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| 28 | [[int result = 0;
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| 29 | char * volatile p = calloc (0, 0);
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| 30 | if (!p)
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| 31 | result |= 1;
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| 32 | free (p);
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| 33 | return result;
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| 34 | ]])],
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| 35 | [],
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| 36 | [ac_cv_func_calloc_0_nonnull=no])
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| 37 | else
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| 38 | case "$host_os" in
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| 39 | # Guess yes on glibc systems.
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| 40 | *-gnu* | gnu*) ac_cv_func_calloc_0_nonnull="guessing yes" ;;
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| 41 | # Guess yes on musl systems.
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| 42 | *-musl*) ac_cv_func_calloc_0_nonnull="guessing yes" ;;
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| 43 | # Guess yes on native Windows.
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| 44 | mingw*) ac_cv_func_calloc_0_nonnull="guessing yes" ;;
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| 45 | # If we don't know, obey --enable-cross-guesses.
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| 46 | *) ac_cv_func_calloc_0_nonnull="$gl_cross_guess_normal" ;;
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| 47 | esac
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| 48 | fi
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| 49 | ])
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| 50 | AS_CASE([$ac_cv_func_calloc_0_nonnull], [*yes], [$1], [$2])
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| 51 | ])
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| 52 |
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| 53 |
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| 54 | # gl_FUNC_CALLOC_GNU
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| 55 | # ------------------
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| 56 | # Replace calloc if it is not compatible with GNU libc.
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| 57 | AC_DEFUN([gl_FUNC_CALLOC_GNU],
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| 58 | [
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| 59 | AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
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| 60 | AC_REQUIRE([gl_FUNC_CALLOC_POSIX])
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| 61 | if test $REPLACE_CALLOC = 0; then
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| 62 | _AC_FUNC_CALLOC_IF([], [REPLACE_CALLOC=1])
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| 63 | fi
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| 64 | ])# gl_FUNC_CALLOC_GNU
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| 65 |
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| 66 | # gl_FUNC_CALLOC_POSIX
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| 67 | # --------------------
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| 68 | # Test whether 'calloc' is POSIX compliant (sets errno to ENOMEM when it
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| 69 | # fails, and doesn't mess up with ptrdiff_t or size_t overflow),
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| 70 | # and replace calloc if it is not.
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| 71 | AC_DEFUN([gl_FUNC_CALLOC_POSIX],
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| 72 | [
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| 73 | AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
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| 74 | AC_REQUIRE([gl_FUNC_MALLOC_POSIX])
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| 75 | if test $REPLACE_MALLOC = 1; then
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| 76 | REPLACE_CALLOC=1
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| 77 | fi
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| 78 | dnl Although in theory we should also test for size_t overflow,
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| 79 | dnl in practice testing for ptrdiff_t overflow suffices
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| 80 | dnl since PTRDIFF_MAX <= SIZE_MAX on all known Gnulib porting targets.
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| 81 | dnl A separate size_t test would slow down 'configure'.
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| 82 | ])
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