1 files changed, 99 insertions, 0 deletions
diff --git a/gnulib-tests/test-fgetc.c b/gnulib-tests/test-fgetc.c
new file mode 100644
index 0000000..2b289dc
--- /dev/null
+++ b/gnulib-tests/test-fgetc.c
@@ -0,0 +1,99 @@
+/* Test of fgetc() function.
+   Copyright (C) 2011-2022 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, see <https://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+#include <stdio.h>
+
+#include "signature.h"
+SIGNATURE_CHECK (fgetc, int, (FILE *));
+
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#if HAVE_MSVC_INVALID_PARAMETER_HANDLER
+# include "msvc-inval.h"
+#endif
+
+#include "macros.h"
+
+int
+main (int argc, char **argv)
+{
+  const char *filename = "test-fgetc.txt";
+
+  /* We don't have an fgetc() function that installs an invalid parameter
+     handler so far.  So install that handler here, explicitly.  */
+#if HAVE_MSVC_INVALID_PARAMETER_HANDLER \
+    && MSVC_INVALID_PARAMETER_HANDLING == DEFAULT_HANDLING
+  gl_msvc_inval_ensure_handler ();
+#endif
+
+  /* Prepare a file.  */
+  {
+    const char text[] = "hello world";
+    int fd = open (filename, O_RDWR | O_CREAT | O_TRUNC, 0600);
+    ASSERT (fd >= 0);
+    ASSERT (write (fd, text, sizeof (text)) == sizeof (text));
+    ASSERT (close (fd) == 0);
+  }
+
+  /* Test that fgetc() sets errno if someone else closes the stream
+     fd behind the back of stdio.  */
+  {
+    FILE *fp = fopen (filename, "r");
+    ASSERT (fp != NULL);
+    ASSERT (close (fileno (fp)) == 0);
+    errno = 0;
+    ASSERT (fgetc (fp) == EOF);
+    ASSERT (errno == EBADF);
+    ASSERT (ferror (fp));
+    fclose (fp);
+  }
+
+  /* Test that fgetc() sets errno if the stream was constructed with
+     an invalid file descriptor.  */
+  {
+    FILE *fp = fdopen (-1, "r");
+    if (fp != NULL)
+      {
+        errno = 0;
+        ASSERT (fgetc (fp) == EOF);
+        ASSERT (errno == EBADF);
+        ASSERT (ferror (fp));
+        fclose (fp);
+      }
+  }
+  {
+    FILE *fp;
+    close (99);
+    fp = fdopen (99, "r");
+    if (fp != NULL)
+      {
+        errno = 0;
+        ASSERT (fgetc (fp) == EOF);
+        ASSERT (errno == EBADF);
+        ASSERT (ferror (fp));
+        fclose (fp);
+      }
+  }
+
+  /* Clean up.  */
+  unlink (filename);
+
+  return 0;
+}