glibc/stdio-common/tst-fwrite.c

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/* Derived from the test case in
https://sourceware.org/bugzilla/show_bug.cgi?id=1078. */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#define OUT_SIZE 10000
static int fd;
static void prepare (void);
#define PREPARE(argc, argv) prepare ()
static int do_test (void);
#define TEST_FUNCTION do_test ()
#include "../test-skeleton.c"
static void
prepare (void)
{
fd = create_temp_file ("tst-fwrite.", NULL);
if (fd == -1)
{
puts ("cannot create temporary file");
exit (1);
}
}
static int
do_test (void)
{
FILE* f = fdopen (fd, "w+");
if (f == NULL) {
puts ("cannot create stream");
return 1;
}
puts ("Opened temp file");
if (fwrite ("a", 1, 1, f) != 1)
{
puts ("1st fwrite failed");
return 1;
}
puts ("Wrote a byte");
fflush (f);
char buffer[10000];
size_t i = fread (buffer, 1, sizeof (buffer), f);
printf ("Read %zu bytes\n", i);
for (i = 0; i < OUT_SIZE; i++)
{
if (fwrite ("n", 1, 1, f) != 1)
{
printf ("fwrite in loop round %zu failed\n", i);
return 1;
}
if ((i + 1) % 1000 == 0)
printf ("wrote %zu bytes ...\n", i + 1);
}
printf ("Wrote %i bytes [done]\n", OUT_SIZE);
return 0;
}