add getopt.c

2 files changed, 48 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index 273a07b..4a52efa 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,5 @@
-BINS = ascii class depipe_strings dup fpipe pipe realloc strpbrk strsep tokenizer
+BINS = ascii class depipe_strings dup fpipe pipe realloc strpbrk strsep \
+       tokenizer getopt
 CC = gcc
 DBGFLAGS = -g -O0
 ifdef DEBUG
diff --git a/getopt.c b/getopt.c
new file mode 100644
index 0000000..1da0882
--- /dev/null
+++ b/getopt.c
@@ -0,0 +1,46 @@
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+/* getopt() external variables */
+extern char *optarg;
+extern int optind, opterr, optopt;
+
+int main(int argc, char **argv)
+{
+    int opt;
+    int fname_f = 0, random_f = 0; /* options' flags */
+    char *fname_a = NULL;
+
+    while ((opt = getopt(argc, argv, "o::c")) != -1)
+    {
+        switch (opt)
+        {
+        case 'o':
+            fname_f = 1;
+#if 0       /* optional args to an option can only be of this format: -ofile.txt */
+            if (optarg)
+                fname_a = strdup(optarg);
+#endif      /* we will check optind in the end and that should be the filename */
+            break;
+        case 'c':
+            random_f = 1;
+            break;
+        default: /* '?' */
+            fprintf(stderr, "usage: %s [-o fname] [-c]\n", argv[0]);
+            exit(EXIT_FAILURE);
+        }
+    }
+
+    if (argv[optind])
+        fname_a = strdup(argv[optind]);
+
+    printf("fname_f = %d\nfname_a = %s\nrandom_f = %d\noptind = %d\n", fname_f,
+           fname_a, random_f, optind);
+
+    printf("optind = %s\n", argv[optind]);
+
+    return 0;
+}
+