stdio-common/tst-fwrite.c

   1 /* Derived from the test case in
   2    https://sourceware.org/bugzilla/show_bug.cgi?id=1078.  */
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5 #include <unistd.h>
   6
   7 #define OUT_SIZE 10000
   8
   9
  10 static int fd;
  11
  12 static void prepare (void);
  13 #define PREPARE(argc, argv) prepare ()
  14
  15 static int do_test (void);
  16 #define TEST_FUNCTION do_test ()
  17
  18 #include "../test-skeleton.c"
  19
  20
  21 static void
  22 prepare (void)
  23 {
  24   fd = create_temp_file ("tst-fwrite.", NULL);
  25   if (fd == -1)
  26     {
  27       puts ("cannot create temporary file");
  28       exit (1);
  29     }
  30 }
  31
  32
  33 static int
  34 do_test (void)
  35 {
  36   FILE* f = fdopen (fd, "w+");
  37   if (f == NULL) {
  38     puts ("cannot create stream");
  39     return 1;
  40   }
  41   puts ("Opened temp file");
  42
  43   if (fwrite ("a", 1, 1, f) != 1)
  44     {
  45       puts ("1st fwrite failed");
  46       return 1;
  47     }
  48   puts ("Wrote a byte");
  49   fflush (f);
  50
  51   char buffer[10000];
  52   size_t i = fread (buffer, 1, sizeof (buffer), f);
  53   printf ("Read %zu bytes\n", i);
  54
  55   for (i = 0; i < OUT_SIZE; i++)
  56     {
  57       if (fwrite ("n", 1, 1, f) != 1)
  58         {
  59           printf ("fwrite in loop round %zu failed\n", i);
  60           return 1;
  61         }
  62
  63       if ((i + 1) % 1000 == 0)
  64         printf ("wrote %zu bytes ...\n", i + 1);
  65     }
  66
  67   printf ("Wrote %i bytes [done]\n", OUT_SIZE);
  68
  69   return 0;
  70 }