C 语言多线程怎么读文件高效

C语言---多个线程读取文件，其代码如下：

#include

#include

#include

#include

#include

#include

#define THREAD_NUM 25

typedef struct

{undefined

FILE *_fp

int _nThreadId//第几个线程

sem_t *_semLock

}IDD_THREAD_PARAM

void *ThreadFunc(void *args)

{undefined

char sLine[100+1]

FILE *fpRead = ((IDD_THREAD_PARAM *)args)->_fp

sem_t *semLock = ((IDD_THREAD_PARAM *)args)->_semLock

int nId = ((IDD_THREAD_PARAM *)args)->_nThreadId

sem_wait(semLock)

while(!feof(fpRead))

{undefined

memset(sLine,0,sizeof(sLine))

fgets(sLine,100,fpRead)

fprintf(stderr,"Thread ID-%d:%s",nId,sLine)

}

sem_post(semLock)

}

int main()

{undefined

pthread_t *pThreads

sem_t semLock

pThreads = (pthread_t *)malloc(THREAD_NUM*sizeof(pthread_t))

sem_init(&semLock,0,1)

FILE *fp = fopen("test.txt","r")

//开始线程循环

IDD_THREAD_PARAM param

for(int i=0i

{undefined

memset(param,0,sizeof(IDD_THREAD_PARAM))

param._fp = fp

param._nThreadId = i

param._semLock = &semLock

pthread_create((pThreads+i),NULL,ThreadFunc,param)

}

for(int i=0i

pthread_join(*(pThreads+i),NULL)

free(pThreads)

pThreads = NULL

fclose(fp)

fp = NULL

return 0

}

线程参数，传地址使用动态分配吧，你只用一个buffer，后面的很可能就把前面的给覆盖了。

把所有的输出printf使用一个互斥的信号量同步一下就行了吧，C的标准库不是线程安全的。

---