1 files changed, 72 insertions, 0 deletions
diff --git a/tests/test-select-fd.c b/tests/test-select-fd.c
new file mode 100644
index 00000000..46e95fd4
--- /dev/null
+++ b/tests/test-select-fd.c
@@ -0,0 +1,72 @@
+/* Test of select() substitute, reading or writing from a given file descriptor.
+   Copyright (C) 2008-2022 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 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>, 2008.  */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/select.h>
+
+int
+main (int argc, char *argv[])
+{
+  if (argc == 4)
+    {
+      char mode = argv[1][0];
+
+      if (mode == 'r' || mode == 'w')
+        {
+          int fd = atoi (argv[2]);
+
+          if (fd >= 0)
+            {
+              const char *result_file_name = argv[3];
+              FILE *result_file = fopen (result_file_name, "wb");
+
+              if (result_file != NULL)
+                {
+                  fd_set fds;
+                  struct timeval timeout;
+                  int ret;
+
+                  FD_ZERO (&fds);
+                  FD_SET (fd, &fds);
+                  timeout.tv_sec = 0;
+                  timeout.tv_usec = 10000;
+                  ret = (mode == 'r'
+                         ? select (fd + 1, &fds, NULL, NULL, &timeout)
+                         : select (fd + 1, NULL, &fds, NULL, &timeout));
+                  if (ret < 0)
+                    {
+                      perror ("select failed");
+                      exit (1);
+                    }
+                  if ((ret == 0) != ! FD_ISSET (fd, &fds))
+                    {
+                      fprintf (stderr, "incorrect return value\n");
+                      exit (1);
+                    }
+                  fprintf (result_file, "%d\n", ret);
+                  exit (0);
+                }
+            }
+        }
+    }
+  fprintf (stderr, "Usage: test-select-fd mode fd result-file-name\n");
+  exit (1);
+}