foreach: new module

[ccan] / ccan / foreach / _info

diff --git a/ccan/foreach/_info b/ccan/foreach/_info
new file mode 100644 (file)
index 0000000..a00ee8b
--- /dev/null
+++ b/ccan/foreach/_info
@@ -0,0 +1,70 @@
+#include <stdio.h>
+#include <string.h>
+#include "config.h"
+
+/**
+ * foreach - macro for simple iteration of arrays
+ *
+ * The foreach_int and foreach_ptr macros allow simple iteration of
+ * static arrays.  This is very efficient with good compiler support
+ * (ie. gcc), and not too bad (ie. a few compares and mallocs) for
+ * other compilers.
+ *
+ * License: LGPL (3 or any later version)
+ * Author: Rusty Russell <rusty@rustcorp.com.au>
+ *
+ * Example:
+ *     // Figure out how to get usage: message out of a program.
+ *     #include <ccan/foreach/foreach.h>
+ *     #include <stdio.h>
+ *     #include <stdlib.h>
+ *     #include <string.h>
+ *     #include <err.h>
+ *
+ *     // Returns true if program outputs "usage:"
+ *     static bool try_usage(const char *prog, const char *arg)
+ *     {
+ *             char *command;
+ *             FILE *in;
+ *             int status;
+ *
+ *             command = malloc(strlen(prog) + 1 + strlen(arg) + 1 +
+ *                              sizeof("</dev/null 2>&1 | grep -qiw usage:"));
+ *             sprintf(command, "%s %s </dev/null 2>&1 | grep -qiw usage:",
+ *                     prog, arg);
+ *             in = popen(command, "r");
+ *             if (!in)
+ *                     err(2, "running '%s'", command);
+ *             status = pclose(in);
+ *             free(command);
+ *             return (WIFEXITED(status) && WEXITSTATUS(status) == 0);
+ *     }
+ *
+ *     int main(int argc, char *argv[])
+ *     {
+ *             const char *arg;
+ *
+ *             if (argc != 2)
+ *                     errx(1, "Usage: %s <progname>\n"
+ *                          "Figures out how to get usage message", argv[0]);
+ *             foreach_ptr(arg, "--help", "-h", "--usage", "-?", "") {
+ *                     if (try_usage(argv[1], arg)) {
+ *                             printf("%s %s\n", argv[1], arg);
+ *                             exit(0);
+ *                     }
+ *             }
+ *             printf("%s is unhelpful\n", argv[1]);
+ *             exit(1);
+ *     }
+ */
+int main(int argc, char *argv[])
+{
+       if (argc != 2)
+               return 1;
+
+       if (strcmp(argv[1], "depends") == 0) {
+               return 0;
+       }
+
+       return 1;
+}