Tests for function fwrite().

[gnulib.git] / tests / test-fwrite.c

diff --git a/tests/test-fwrite.c b/tests/test-fwrite.c
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+/* Test of fwrite() function.
+   Copyright (C) 2011 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, 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, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+#include <config.h>
+
+#include <stdio.h>
+
+#include "signature.h"
+SIGNATURE_CHECK (fwrite, size_t, (const void *, size_t, size_t, FILE *));
+
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "macros.h"
+
+int
+main (int argc, char **argv)
+{
+  const char *filename = "test-fwrite.txt";
+
+  /* Test that fwrite() on an unbuffered stream sets errno if someone else
+     closes the stream fd behind the back of stdio.  */
+  {
+    FILE *fp = fopen (filename, "w");
+    char buf[5] = "world";
+    ASSERT (fp != NULL);
+    setvbuf (fp, NULL, _IONBF, 0);
+    ASSERT (close (fileno (fp)) == 0);
+    errno = 0;
+    ASSERT (fwrite (buf, 1, sizeof (buf), fp) == 0);
+    ASSERT (errno == EBADF);
+    ASSERT (ferror (fp));
+    fclose (fp);
+  }
+
+  /* Test that fwrite() on an unbuffered stream sets errno if the stream
+     was constructed with an invalid file descriptor.  */
+  {
+    FILE *fp = fdopen (-1, "w");
+    if (fp != NULL)
+      {
+        char buf[5] = "world";
+        setvbuf (fp, NULL, _IONBF, 0);
+        errno = 0;
+        ASSERT (fwrite (buf, 1, sizeof (buf), fp) == 0);
+        ASSERT (errno == EBADF);
+        ASSERT (ferror (fp));
+        fclose (fp);
+      }
+  }
+  {
+    FILE *fp = fdopen (99, "w");
+    if (fp != NULL)
+      {
+        char buf[5] = "world";
+        setvbuf (fp, NULL, _IONBF, 0);
+        errno = 0;
+        ASSERT (fwrite (buf, 1, sizeof (buf), fp) == 0);
+        ASSERT (errno == EBADF);
+        ASSERT (ferror (fp));
+        fclose (fp);
+      }
+  }
+
+  /* Clean up.  */
+  unlink (filename);
+
+  return 0;
+}