1 files changed, 78 insertions, 0 deletions
diff --git a/gnulib-tests/test-ftell3.c b/gnulib-tests/test-ftell3.c
new file mode 100644
index 0000000..bb4b7b2
--- /dev/null
+++ b/gnulib-tests/test-ftell3.c
@@ -0,0 +1,78 @@
+/* Test of ftell() 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/>.  */
+
+#include <config.h>
+
+/* None of the files accessed by this test are large, so disable the
+   fseek link warning if we are not using the gnulib fseek module.  */
+#define _GL_NO_LARGE_FILES
+#include <stdio.h>
+
+#include <string.h>
+
+#include "macros.h"
+
+#define TESTFILE "t-ftell3.tmp"
+
+int
+main (void)
+{
+  FILE *fp;
+
+  /* Create a file with some contents.  */
+  fp = fopen (TESTFILE, "w");
+  if (fp == NULL)
+    goto skip;
+  if (fwrite ("foogarsh", 1, 8, fp) < 8)
+    goto skip;
+  if (fclose (fp))
+    goto skip;
+
+  /* The file's contents is now "foogarsh".  */
+
+  /* Try writing after reading to EOF.  */
+  fp = fopen (TESTFILE, "r+");
+  if (fp == NULL)
+    goto skip;
+  if (fseek (fp, -1, SEEK_END))
+    goto skip;
+  ASSERT (getc (fp) == 'h');
+  ASSERT (getc (fp) == EOF);
+  ASSERT (ftell (fp) == 8);
+  ASSERT (ftell (fp) == 8);
+  ASSERT (putc ('!', fp) == '!');
+  ASSERT (ftell (fp) == 9);
+  ASSERT (fclose (fp) == 0);
+  fp = fopen (TESTFILE, "r");
+  if (fp == NULL)
+    goto skip;
+  {
+    char buf[10];
+    ASSERT (fread (buf, 1, 10, fp) == 9);
+    ASSERT (memcmp (buf, "foogarsh!", 9) == 0);
+  }
+  ASSERT (fclose (fp) == 0);
+
+  /* The file's contents is now "foogarsh!".  */
+
+  remove (TESTFILE);
+  return 0;
+
+ skip:
+  fprintf (stderr, "Skipping test: prerequisite file operations failed.\n");
+  remove (TESTFILE);
+  return 77;
+}