1 files changed, 60 insertions, 0 deletions
diff --git a/src/grep/gnulib-tests/test-ftruncate.c b/src/grep/gnulib-tests/test-ftruncate.c
new file mode 100644
index 0000000..d11b8eb
--- /dev/null
+++ b/src/grep/gnulib-tests/test-ftruncate.c
@@ -0,0 +1,60 @@
+/* Test truncating a file.
+   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 <unistd.h>
+
+#include "signature.h"
+SIGNATURE_CHECK (ftruncate, int, (int, off_t));
+
+#include <errno.h>
+#include <fcntl.h>
+
+#include "macros.h"
+
+int
+main (int argc, char *argv[])
+{
+  const char *filename = argv[1];
+
+  /* Test behaviour for invalid file descriptors.  */
+  {
+    errno = 0;
+    ASSERT (ftruncate (-1, 0) == -1);
+    ASSERT (errno == EBADF);
+  }
+  {
+    close (99);
+    errno = 0;
+    ASSERT (ftruncate (99, 0) == -1);
+    ASSERT (errno == EBADF);
+  }
+
+  /* Test behaviour for read-only file descriptors.  */
+  {
+    int fd = open (filename, O_RDONLY);
+    ASSERT (fd >= 0);
+    errno = 0;
+    ASSERT (ftruncate (fd, 0) == -1);
+    ASSERT (errno == EBADF || errno == EINVAL
+            || errno == EACCES /* seen on mingw */
+           );
+    close (fd);
+  }
+
+  return 0;
+}