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我刚开始学习如何混淆线程和C中的同步编程。我试图编写一个使用线程(POSIX接口)从共享缓冲区中读取选定文件的阅读器。子线程将从缓冲区中检索文件名,而父线程将不定期地从stdin读取文件名并将它们放入缓冲区。我究竟做错了什么?共享缓冲区和同步编程的问题
pthread_mutex_t lock;
static char* files[NFILES];
int top = NFILES-1;
void putInBuffer(char* file){
pthread_mutex_lock(&lock);
if(top < NFILES-1){
files[top] = file;
top++;
}
pthread_mutex_unlock(&lock);
}
char* removeFromBuffer(){
char* file;
pthread_mutex_lock(&lock);
file = files[top];
top--;
pthread_mutex_unlock(&lock);
return file;
}
void* leitor(){
int op,i,r,cl;
char* file;
char buff[NCHARS];
char teste[NCHARS];
while(1){
pthread_mutex_lock(&lock);
file = removeFromBuffer();
printf("%s\n", file);
op = open(file, O_RDONLY);
if(op == -1) {
perror("Open unsuccessful");
pthread_exit((void*)-1);
}
r = read(op, teste, NBYTES);
if(r == -1){
perror("Read unsuccessful");
pthread_exit((void*)-1);
}
for(i=0; i<NLINES-1; i++){
r = read(op, buff, NBYTES);
if(r == -1){
perror("Read unsuccessful");
pthread_exit((void*)-1);
}
if(strcmp(buff,teste) != 0){
perror("Incorrect file");
pthread_exit((void*)-1);
}
}
cl = close (op);
if(cl == -1){
perror("Close unsuccessful");
pthread_exit((void*)-1);
}
printf("Correct file: %s\n", file);
pthread_mutex_unlock(&lock);
}
pthread_exit((void*)0);
return NULL;
}
int main(){
pthread_t threads[NTHREADS];
int i,*status;
char file[LENFILENAME];
if (pthread_mutex_init(&lock, NULL))
{
perror("\n mutex init failed\n");
exit(-1);
}
for(i=0;i<NTHREADS;i++){
if(pthread_create(&(threads[i]),NULL, leitor,NULL)){
perror("Failed to create thread");
exit(-1);
}
}
while(1){
read(STDIN_FILENO, file, LENFILENAME);
printf("%s\n", file);
putInBuffer(file);
printf("%s\n", removeFromBuffer());
}
for (i=0;i<NTHREADS;i++){
if(pthread_join(threads[i],(void**)&status)){
perror("Failed to join thread");
exit(-1);
}
printf("Thread returned %d\n", status);
}
pthread_mutex_destroy(&lock);
return 0;
}
感谢您的帮助:) – 2014-12-03 20:40:30