queue

A thread safe type-agnostic header-only macro-based structure queue implementation in C.

Usage

Include the queue.h header file in your source. To create a queueable structure, include the queue_handle qh member in the struct definition.

Before any other operations, ensure that QUEUE_INIT has been called, it is an error to not do so. This initialises the queue and sets up the mutex and conditions variables. Setting the queue to NULL will protect against errors if a queue has not been

Freeing the queue does not free every element in the queue if they have been dynamically allocated. This has to be done by popping all the elements in the queue and freeing them manually.

Pushing the same element (at the same address) into the queue is not supported and is an error. This is because the next member of the queue's queue_handle will be overwritten. This will cause undefined behavior when pushing or popping to or from the queue (see commented out test case).

#include <stdlib.h>
#include <stdio.h>
#include "queue.h"

struct msg {
    char *content;
    queue_handle qh;
};

int main(void) {
    struct msg *msgs; // message queue
    struct msg m1, *m2;

    QUEUE_INIT(struct msg, msgs);

    m1.content = "abc";
    QUEUE_PUSH(msgs, &m1);

    printf("msgs size: %d\n", QUEUE_SIZE(msgs)); // msgs size: 1

    QUEUE_POP(msgs, m2);
    printf("m2 content: %s\n", m2->content); // m2 content: abc

    QUEUE_FREE(msgs);

    return EXIT_SUCCESS;
}

Testing and building examples

To run tests run

make check

To compile the examples run

make examples

Both of the above can be done together by running

make