使用openmp的Reader-Writer

Question

我试图使用openmp来实现读写器问题。当输入器在输入输入之前获取锁定时，一些读者会读取缓冲区。我使用fgets（）从stdin获取输入。理想情况下，光标应停在输入输入的位置。任何人都可以向我解释一下这里发生了什么。代码如下

#include<stdio.h>
#include<omp.h>
omp_lock_t r;
omp_lock_t w;
char buffer[10];
int rw=0;
int nr,nw;
void start_read(){
    omp_set_lock(&r);
    nr++;
    if(nr==1){
      omp_set_lock(&w);
      printf("Reader acquired lock\n");
    }
    omp_unset_lock(&r);
}
void end_read(){
    omp_set_lock(&r);
    nr--;
    if(nr==0){

       omp_unset_lock(&w);
       printf("Reader released lock\n");
     }
    omp_unset_lock(&r);
}
void writer_part(){
    omp_set_lock(&w);
    printf("\nWriter acquired lock\n");
    printf("thread %d writing contents --\n",omp_get_thread_num());
    printf("change contents of the buffer\n");
    fgets(buffer,10,stdin);
    printf("%s",buffer);
    omp_unset_lock(&w);
    printf("Writer released lock\n");   
}
void reader_part(){
    start_read();
    printf("thread %d Reading contents -- %s",omp_get_thread_num(),buffer);
    printf("\n");
    end_read();
}


int main(){
int i;
omp_set_num_threads(8);
omp_init_lock(&r);
omp_init_lock(&w);
printf("enter the number of writers\n");
scanf("%d",&nw);
printf("enter number of readers\n");
scanf("%d",&nr);
getchar();
printf("initiliaze the buffer\n");
fgets(buffer,10,stdin);
printf("%s",buffer);

#pragma omp parallel for
for(i=0;i<(nr+nw);i++){
    if(i<nw){
    writer_part();  
    }else{
    reader_part();
    }
}
printf("\n\n");
return 0;
}

输出为