1 files changed, 70 insertions, 0 deletions
diff --git a/src/gl/tests/test-ftello4.c b/src/gl/tests/test-ftello4.c
new file mode 100644
index 0000000..5f4c14b
--- /dev/null
+++ b/src/gl/tests/test-ftello4.c
@@ -0,0 +1,70 @@
+/* Test of ftello() function.
+   Copyright (C) 2011-2021 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 <config.h>
+
+#include <stdio.h>
+
+#include <errno.h>
+#include <unistd.h>
+
+#include "macros.h"
+
+int
+main (int argc, char **argv)
+{
+  const char *filename = argv[1];
+
+  /* Test that ftello() sets errno if someone else closes the stream
+     fd behind the back of stdio.  */
+  {
+    FILE *fp = fopen (filename, "r");
+    ASSERT (fp != NULL);
+    setvbuf (fp, NULL, _IONBF, 0);
+    ASSERT (close (fileno (fp)) == 0);
+    errno = 0;
+    ASSERT (ftello (fp) == (off_t)-1);
+    ASSERT (errno == EBADF);
+    fclose (fp);
+  }
+
+  /* Test that ftello() sets errno if the stream was constructed with
+     an invalid file descriptor.  */
+  {
+    FILE *fp = fdopen (-1, "w");
+    if (fp != NULL)
+      {
+        errno = 0;
+        ASSERT (ftello (fp) == (off_t)-1);
+        ASSERT (errno == EBADF);
+        fclose (fp);
+      }
+  }
+  {
+    FILE *fp;
+    close (99);
+    fp = fdopen (99, "w");
+    if (fp != NULL)
+      {
+        errno = 0;
+        ASSERT (ftello (fp) == (off_t)-1);
+        ASSERT (errno == EBADF);
+        fclose (fp);
+      }
+  }
+
+  return 0;
+}