c语言实现队列 Linux

#include <iostream>
#include <pthread.h>
int report_msg_queue_length;
pthread_mutex_t report_msg_queue_mutex;
struct report_msg_queue_node{
    report_msg_queue_node* prev;
    report_msg_queue_node* next;
    char * data;
};
report_msg_queue_node * report_msg_queue_start;
report_msg_queue_node * report_msg_queue_end;
void report_msg_queue_init(){
    pthread_mutex_init(&report_msg_queue_mutex,NULL);
    report_msg_queue_length=0;
    report_msg_queue_start=(struct report_msg_queue_node *)malloc(sizeof(struct report_msg_queue_node));
    report_msg_queue_start->prev=NULL;
    report_msg_queue_start->next=NULL;
    report_msg_queue_end=report_msg_queue_start;
}

void report_msg_queue_push(char * msg){
    pthread_mutex_lock(&report_msg_queue_mutex);
    if(report_msg_queue_start->data==NULL){
        report_msg_queue_start->data=msg;
        pthread_mutex_unlock(&report_msg_queue_mutex);
    }else{
        report_msg_queue_node* report_msg_queue_temp = (struct report_msg_queue_node *)malloc(sizeof(struct report_msg_queue_node));
        report_msg_queue_temp->prev=NULL;
        report_msg_queue_temp->next=report_msg_queue_start;
        report_msg_queue_temp->data=msg;
        report_msg_queue_start->prev=report_msg_queue_temp;
        report_msg_queue_start = report_msg_queue_temp;
        pthread_mutex_unlock(&report_msg_queue_mutex);
    }
}

char * report_msg_queue_pop(){
    pthread_mutex_lock(&report_msg_queue_mutex);
    if(report_msg_queue_end->data==NULL){
        pthread_mutex_unlock(&report_msg_queue_mutex);
        return NULL;
    }else{
        char * ret = report_msg_queue_end->data;
        if(report_msg_queue_end->prev!=NULL){
            report_msg_queue_node * temp = report_msg_queue_end;
            report_msg_queue_end= report_msg_queue_end->prev;
            free(temp);
        }else{
            report_msg_queue_end->data=NULL;
        }
        pthread_mutex_unlock(&report_msg_queue_mutex);
        return  ret;
    }
}

int main() {

    report_msg_queue_init();

    for (int i = 0; i <100 ; ++i) {
        report_msg_queue_push("1");
        report_msg_queue_push("2");
        report_msg_queue_push("3");
        report_msg_queue_push("4");
        char * ch;
        while (ch = report_msg_queue_pop()){
            printf("%s\n",ch);
        }
    }


    return 0;
}