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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 17:39:29 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 17:39:29 +0000
commit8ffec2a3aba6f114784e11f89ef1d57a096ae540 (patch)
treeccebcbad06203e8241a8e7249f8e6c478a3682ea /gnulib-tests/null-ptr.h
parentInitial commit. (diff)
downloadcoreutils-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 'gnulib-tests/null-ptr.h')
-rw-r--r--gnulib-tests/null-ptr.h33
1 files changed, 33 insertions, 0 deletions
diff --git a/gnulib-tests/null-ptr.h b/gnulib-tests/null-ptr.h
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+/* Return a NULL pointer, without letting the compiler know it.
+ Copyright (C) 2017-2020 Free Software Foundation, Inc.
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <https://www.gnu.org/licenses/>. */
+
+#include <stdlib.h>
+
+/* Return NULL.
+ Usual compilers are not able to infer something about the return value. */
+static void *
+null_ptr (void)
+{
+ unsigned int x = rand ();
+ unsigned int y = x * x;
+ if (y & 2)
+ return (void *) -1;
+ else
+ return (void *) 0;
+}
+
+/* If you want to know why this always returns NULL, read
+ https://en.wikipedia.org/wiki/Quadratic_residue#Prime_power_modulus . */