tal/path: fix unset vars in error paths.

[ccan] / ccan / tal / _info

diff --git a/ccan/tal/_info b/ccan/tal/_info
index 3f7c22c717d93b0e69182c2a55de8db27ff85e82..0d75f56e0ed6a7f975d39640402672a6868c69b9 100644 (file)
--- a/ccan/tal/_info
+++ b/ccan/tal/_info
@@ -12,27 +12,29 @@
  * This allows you to build complex objects based on their lifetimes, eg:
  *
  *  struct foo *X = tal(NULL, struct foo);
- *  X->name = tal_strdup(X, "foo");
+ *  X->val = tal(X, int);
  *
- * and the pointer X->name would be a "child" of the tal context "X";
- * tal_free(X->name) would free X->name as expected, by tal_free(X) would
- * free X and X->name.
+ * and the pointer X->val would be a "child" of the tal context "X";
+ * tal_free(X->val) would free X->val as expected, by tal_free(X) would
+ * free X and X->val.
  *
  * With an overhead of approximately 4 pointers per object
  * (vs. talloc's 12 pointers), it uses dynamic allocation for
  * destructors and child lists, so those operations can fail.  It does
  * not support talloc's references or failing destructors.
  *
+ * See Also:
+ *     ccan/tal/str (useful string helpers)
+ *
  * Example:
  *     #include <stdio.h>
- *     #include <stdarg.h>
  *     #include <err.h>
  *     #include <ccan/talloc/talloc.h>
  *
  *     // A structure containing a popened command.
  *     struct command {
  *             FILE *f;
- *             const char *command;
+ *             char *command;
  *     };
  *
  *     // When struct command is freed, we also want to pclose pipe.
@@ -43,21 +45,22 @@
  *
  *     // This function opens a writable pipe to the given command.
  *     static struct command *open_output_cmd(const tal_t *ctx,
- *                                            const char *fmt, ...)
+ *                                            const char *a0, const char *a1)
  *     {
- *             va_list ap;
  *             struct command *cmd = tal(ctx, struct command);
  *
  *             if (!cmd)
  *                     return NULL;
  *
- *             va_start(ap, fmt);
- *             cmd->command = tal_vasprintf(cmd, fmt, ap);
- *             va_end(ap);
+ *             // Note that tal/str has helpers to make this much easier!
+ *             cmd->command = tal_arrz(cmd, char, strlen(a0) + strlen(a1) + 2);
  *             if (!cmd->command) {
  *                     tal_free(cmd);
  *                     return NULL;
  *             }
+ *             strcat(cmd->command, a0);
+ *             strcat(cmd->command, " ");
+ *             strcat(cmd->command, a1);
  *
  *             cmd->f = popen(cmd->command, "w");
  *             if (!cmd->f) {
@@ -75,7 +78,7 @@
  *             if (argc != 2)
  *                     errx(1, "Usage: %s <command>\n", argv[0]);
  *
- *             cmd = open_output_cmd(NULL, "%s hello", argv[1]);
+ *             cmd = open_output_cmd(NULL, argv[1], "hello");
  *             if (!cmd)
  *                     err(1, "Running '%s hello'", argv[1]);
  *             fprintf(cmd->f, "This is a test\n");
@@ -91,6 +94,7 @@ int main(int argc, char *argv[])
                return 1;
 
        if (strcmp(argv[1], "depends") == 0) {
+               printf("ccan/alignof\n");
                printf("ccan/compiler\n");
                printf("ccan/likely\n");
                printf("ccan/list\n");