glibc/libio/tst-fclose-unopened2.c

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/* Test using fclose on an unopened file.
Copyright (C) 2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <mcheck.h>
#include <stdio.h>
#include <support/check.h>
/* Verify that fclose on an unopened file returns EOF. This test uses
a file with an allocated buffer.
This is not part of the fclose external contract but there are
dependencies on this behaviour. */
static int
do_test (void)
{
mtrace ();
/* Input file tst-fclose-unopened2.input has 6 bytes plus newline. */
char buf[6];
/* Read from the file to ensure its internal buffer is allocated. */
TEST_COMPARE (fread (buf, 1, sizeof (buf), stdin), sizeof (buf));
TEST_COMPARE (fclose (stdin), 0);
/* Attempt to close the unopened file and verify that EOF is returned.
Calling fclose on a file twice normally causes a use-after-free bug,
however the standard streams are an exception since they are not
deallocated by fclose. */
TEST_COMPARE (fclose (stdin), EOF);
return 0;
}
#include <support/test-driver.c>