1 files changed, 78 insertions, 0 deletions
diff --git a/libc/manual/examples/subopt.c b/libc/manual/examples/subopt.c
new file mode 100644
index 000000000..287fe8c49
--- /dev/null
+++ b/libc/manual/examples/subopt.c
@@ -0,0 +1,78 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+int do_all;
+const char *type;
+int read_size;
+int write_size;
+int read_only;
+
+enum
+{
+  RO_OPTION = 0,
+  RW_OPTION,
+  READ_SIZE_OPTION,
+  WRITE_SIZE_OPTION,
+  THE_END
+};
+
+const char *mount_opts[] =
+{
+  [RO_OPTION] = "ro",
+  [RW_OPTION] = "rw",
+  [READ_SIZE_OPTION] = "rsize",
+  [WRITE_SIZE_OPTION] = "wsize",
+  [THE_END] = NULL
+};
+
+int
+main (int argc, char *argv[])
+{
+  char *subopts, *value;
+  int opt;
+
+  while ((opt = getopt (argc, argv, "at:o:")) != -1)
+    switch (opt)
+      {
+      case 'a':
+        do_all = 1;
+        break;
+      case 't':
+        type = optarg;
+        break;
+      case 'o':
+        subopts = optarg;
+        while (*subopts != '\0')
+          switch (getsubopt (&subopts, mount_opts, &value))
+            {
+            case RO_OPTION:
+              read_only = 1;
+              break;
+            case RW_OPTION:
+              read_only = 0;
+              break;
+            case READ_SIZE_OPTION:
+              if (value == NULL)
+                abort ();
+              read_size = atoi (value);
+              break;
+            case WRITE_SIZE_OPTION:
+              if (value == NULL)
+                abort ();
+              write_size = atoi (value);
+              break;
+            default:
+              /* Unknown suboption.  */
+              printf ("Unknown suboption `%s'\n", value);
+              break;
+            }
+        break;
+      default:
+        abort ();
+      }
+
+  /* Do the real work.  */
+
+  return 0;
+}