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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 17:39:29 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 17:39:29 +0000 |
commit | 8ffec2a3aba6f114784e11f89ef1d57a096ae540 (patch) | |
tree | ccebcbad06203e8241a8e7249f8e6c478a3682ea /m4/flexmember.m4 | |
parent | Initial commit. (diff) | |
download | coreutils-8ffec2a3aba6f114784e11f89ef1d57a096ae540.tar.xz coreutils-8ffec2a3aba6f114784e11f89ef1d57a096ae540.zip |
Adding upstream version 8.32.upstream/8.32upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'm4/flexmember.m4')
-rw-r--r-- | m4/flexmember.m4 | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/m4/flexmember.m4 b/m4/flexmember.m4 new file mode 100644 index 0000000..90f3ddd --- /dev/null +++ b/m4/flexmember.m4 @@ -0,0 +1,44 @@ +# serial 5 +# Check for flexible array member support. + +# Copyright (C) 2006, 2009-2020 Free Software Foundation, Inc. +# This file is free software; the Free Software Foundation +# gives unlimited permission to copy and/or distribute it, +# with or without modifications, as long as this notice is preserved. + +# Written by Paul Eggert. + +AC_DEFUN([AC_C_FLEXIBLE_ARRAY_MEMBER], +[ + AC_CACHE_CHECK([for flexible array member], + ac_cv_c_flexmember, + [AC_COMPILE_IFELSE( + [AC_LANG_PROGRAM( + [[#include <stdlib.h> + #include <stdio.h> + #include <stddef.h> + struct m { struct m *next, **list; char name[]; }; + struct s { struct s *p; struct m *m; int n; double d[]; };]], + [[int m = getchar (); + size_t nbytes = offsetof (struct s, d) + m * sizeof (double); + nbytes += sizeof (struct s) - 1; + nbytes -= nbytes % sizeof (struct s); + struct s *p = malloc (nbytes); + p->p = p; + p->m = NULL; + p->d[0] = 0.0; + return p->d != (double *) NULL;]])], + [ac_cv_c_flexmember=yes], + [ac_cv_c_flexmember=no])]) + if test $ac_cv_c_flexmember = yes; then + AC_DEFINE([FLEXIBLE_ARRAY_MEMBER], [], + [Define to nothing if C supports flexible array members, and to + 1 if it does not. That way, with a declaration like 'struct s + { int n; short d@<:@FLEXIBLE_ARRAY_MEMBER@:>@; };', the struct hack + can be used with pre-C99 compilers. + Use 'FLEXSIZEOF (struct s, d, N * sizeof (short))' to calculate + the size in bytes of such a struct containing an N-element array.]) + else + AC_DEFINE([FLEXIBLE_ARRAY_MEMBER], [1]) + fi +]) |