1 files changed, 70 insertions, 0 deletions
diff --git a/gnulib-tests/test-fseek.c b/gnulib-tests/test-fseek.c
new file mode 100644
index 0000000..161a53e
--- /dev/null
+++ b/gnulib-tests/test-fseek.c
@@ -0,0 +1,70 @@
+/* Test of fseek() function.
+   Copyright (C) 2007-2023 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/>.  */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2007.  */
+
+#include <config.h>
+
+/* None of the files accessed by this test are large, so disable the
+   fseek link warning if the user requested GNULIB_POSIXCHECK.  */
+#define _GL_NO_LARGE_FILES
+#include <stdio.h>
+
+#include "signature.h"
+SIGNATURE_CHECK (fseek, int, (FILE *, long, int));
+
+#include "macros.h"
+
+#ifndef FUNC_UNGETC_BROKEN
+# define FUNC_UNGETC_BROKEN 0
+#endif
+
+int
+main (int argc, char **argv)
+{
+  /* Assume stdin is non-empty, seekable, and starts with '#!/bin/sh'
+     iff argc > 1.  */
+  int expected = argc > 1 ? 0 : -1;
+  ASSERT (fseek (stdin, 0, SEEK_CUR) == expected);
+  if (argc > 1)
+    {
+      /* Test that fseek discards previously read ungetc data.  */
+      int ch = fgetc (stdin);
+      ASSERT (ch == '#');
+      ASSERT (ungetc (ch, stdin) == ch);
+      ASSERT (fseek (stdin, 2, SEEK_SET) == 0);
+      ch = fgetc (stdin);
+      ASSERT (ch == '/');
+      if (2 < argc)
+        {
+          if (FUNC_UNGETC_BROKEN)
+            {
+              fputs ("Skipping test: ungetc cannot handle arbitrary bytes\n",
+                     stderr);
+              return 77;
+            }
+          /* Test that fseek discards random ungetc data.  */
+          ASSERT (ungetc (ch ^ 0xff, stdin) == (ch ^ 0xff));
+        }
+      ASSERT (fseek (stdin, 0, SEEK_END) == 0);
+      ASSERT (fgetc (stdin) == EOF);
+      /* Test that fseek resets end-of-file marker.  */
+      ASSERT (feof (stdin));
+      ASSERT (fseek (stdin, 0, SEEK_END) == 0);
+      ASSERT (!feof (stdin));
+    }
+  return 0;
+}