A queue implementation in C

queue.c

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

struct queue *queue_new(void)
{
	struct queue *q;

	q = malloc(sizeof(struct queue));
	q->base = NULL;
	q->size = 0;

	return q;
}

void queue_push(struct queue *q, void *elem)
{
	struct queue_elem **qeptr;

	for (qeptr = &q->base; *qeptr != NULL; qeptr = &(*qeptr)->next);

	*qeptr = malloc(sizeof(struct queue_elem));
	(*qeptr)->next = NULL;
	(*qeptr)->data = elem;
	++q->size;
}

void *queue_pop(struct queue *q)
{
	struct queue_elem *top;
	void *data;

	if (queue_empty(q)) {
		fprintf(stderr, "%s: queue is empty\n", __func__);
		return NULL;
	}
	top = q->base;
	q->base = top->next;
	data = top->data;
	free(top);
	--q->size;
	return data;
}

void queue_destroy(struct queue *q)
{
	while (!queue_empty(q))
		queue_pop(q);
	free(q);
}

queue.h

#ifndef _QUEUE_H
#define _QUEUE_H

struct queue_elem {
	struct queue_elem *next;
	void *data;
};

struct queue {
	struct queue_elem *base;
	int size;
};

struct queue *queue_new(void);

void queue_push(struct queue *q, void *elem);

void *queue_pop(struct queue *q);

#define queue_empty(q) ((q)->size == 0)

void queue_destroy(struct queue *q);

#endif /* _QUEUE_H */