| #include <stdio.h> |
| #include <string.h> |
| #include "config.h" |
| |
| /** |
| * container_of - routine for upcasting |
| * |
| * It is often convenient to create code where the caller registers a pointer |
| * to a generic structure and a callback. The callback might know that the |
| * pointer points to within a larger structure, and container_of gives a |
| * convenient and fairly type-safe way of returning to the enclosing structure. |
| * |
| * This idiom is an alternative to providing a void * pointer for every |
| * callback. |
| * |
| * Example: |
| * #include <stdio.h> |
| * #include <ccan/container_of/container_of.h> |
| * |
| * struct timer { |
| * void *members; |
| * }; |
| * |
| * struct info { |
| * int my_stuff; |
| * struct timer timer; |
| * }; |
| * |
| * static void register_timer(struct timer *timer) |
| * { |
| * //... |
| * } |
| * |
| * static void my_timer_callback(struct timer *timer) |
| * { |
| * struct info *info = container_of(timer, struct info, timer); |
| * printf("my_stuff is %u\n", info->my_stuff); |
| * } |
| * |
| * int main(void) |
| * { |
| * struct info info = { .my_stuff = 1 }; |
| * |
| * register_timer(&info.timer); |
| * // ... |
| * return 0; |
| * } |
| * |
| * License: CC0 (Public domain) |
| * Author: Rusty Russell <rusty@rustcorp.com.au> |
| */ |
| int main(int argc, char *argv[]) |
| { |
| if (argc != 2) |
| return 1; |
| |
| if (strcmp(argv[1], "depends") == 0) { |
| printf("ccan/check_type\n"); |
| return 0; |
| } |
| |
| return 1; |
| } |