| 1 | // SPDX-FileCopyrightText: 2013 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 2 | // |
| 3 | // SPDX-License-Identifier: MIT |
| 4 | |
| 5 | /* |
| 6 | * This example shows how to dequeue nodes from a wfcqueue. |
| 7 | */ |
| 8 | |
| 9 | #include <stdio.h> |
| 10 | #include <stdlib.h> |
| 11 | |
| 12 | #include <urcu/wfcqueue.h> /* Wait-free concurrent queue */ |
| 13 | #include <urcu/compiler.h> /* For CAA_ARRAY_SIZE */ |
| 14 | |
| 15 | /* |
| 16 | * Nodes populated into the queue. |
| 17 | */ |
| 18 | struct mynode { |
| 19 | int value; /* Node content */ |
| 20 | struct cds_wfcq_node node; /* Chaining in queue */ |
| 21 | }; |
| 22 | |
| 23 | int main(void) |
| 24 | { |
| 25 | int values[] = { -5, 42, 36, 24, }; |
| 26 | struct cds_wfcq_head myqueue_head; /* Queue head */ |
| 27 | struct cds_wfcq_tail myqueue_tail; /* Queue tail */ |
| 28 | unsigned int i; |
| 29 | int ret = 0; |
| 30 | |
| 31 | cds_wfcq_init(&myqueue_head, &myqueue_tail); |
| 32 | |
| 33 | /* |
| 34 | * Enqueue nodes. |
| 35 | */ |
| 36 | for (i = 0; i < CAA_ARRAY_SIZE(values); i++) { |
| 37 | struct mynode *node; |
| 38 | |
| 39 | node = malloc(sizeof(*node)); |
| 40 | if (!node) { |
| 41 | ret = -1; |
| 42 | goto end; |
| 43 | } |
| 44 | |
| 45 | cds_wfcq_node_init(&node->node); |
| 46 | node->value = values[i]; |
| 47 | cds_wfcq_enqueue(&myqueue_head, &myqueue_tail, |
| 48 | &node->node); |
| 49 | } |
| 50 | |
| 51 | /* |
| 52 | * Dequeue each node from the queue. Those will be dequeued from |
| 53 | * the oldest (first enqueued) to the newest (last enqueued). |
| 54 | */ |
| 55 | printf("dequeued content:"); |
| 56 | for (;;) { |
| 57 | struct cds_wfcq_node *qnode; |
| 58 | struct mynode *node; |
| 59 | |
| 60 | qnode = cds_wfcq_dequeue_blocking(&myqueue_head, &myqueue_tail); |
| 61 | if (!qnode) { |
| 62 | break; /* Queue is empty. */ |
| 63 | } |
| 64 | /* Getting the container structure from the node */ |
| 65 | node = caa_container_of(qnode, struct mynode, node); |
| 66 | printf(" %d", node->value); |
| 67 | free(node); |
| 68 | } |
| 69 | printf("\n"); |
| 70 | end: |
| 71 | cds_wfcq_destroy(&myqueue_head, &myqueue_tail); |
| 72 | return ret; |
| 73 | } |