我目前是一名初学者,学习如何在 C 中使用 pthreads。我的代码目前正在运行,因此没有实际的错误,但它没有它应该做什么。代码应提示用户输入每个问题,然后在用户输入其信息后打印所有结果,但输入名称后代码似乎会跳过并完成。请有人帮我找到我的代码出错的地方吗? 下面是我的代码和运行时的输出:
#include <stdio.h
#include <stdlib.h>
#include <pthread.h>
#include <semaphore.h>
#include <sched.h>
#include <unistd.h>
#include <signal.h>
#include <sys/types.h>
#include <string.h>
#include <pthread.h>
pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
typedef struct compound {
char name [1024];
int age;
int birthMonth;
int birthYear;
int threadNumber;
}compound;
void * threadName (void * param){
compound *lparam = (compound *) param;
int lock;
lock = pthread_mutex_lock(&mutex);
printf ("> Please type your name for thread %dn", lparam->threadNumber);
scanf ("%c", lparam->name);
lock = pthread_mutex_unlock(&mutex);
lock = pthread_mutex_lock(&mutex);
printf ("> Please type your age for thread %dn", lparam->threadNumber);
scanf ("%d", &(lparam->age));
lock = pthread_mutex_unlock(&mutex);
lock = pthread_mutex_lock(&mutex);
printf ("> Please type your birth month for thread %dn", lparam->threadNumber);
scanf ("%d", &(lparam->birthMonth));
lock = pthread_mutex_unlock(&mutex);
lock = pthread_mutex_lock(&mutex);
printf ("> Please type your birth year for thread %dn", lparam->threadNumber);
scanf ("%d", &(lparam->birthYear));
lock = pthread_mutex_unlock(&mutex);
return NULL;
}
// main function
int main ( void) {
pthread_t thread_ID3, thread_ID4;
void *exitstatus;
compound first, second;
first.threadNumber= 1;
second.threadNumber = 2;
pthread_create (&thread_ID3, NULL, threadName, &first);
pthread_create (&thread_ID4, NULL, threadName, &second);
pthread_join (thread_ID3, &exitstatus);
pthread_join (thread_ID4, &exitstatus);
printf("Finishedn");
getchar();
return 0;
}
This is what happens when the code is executed:
[370user14@nostromo ex2]$ make
gcc -Wall -c base_code.c
gcc -lm -lpthread base_code.o -o baseprog
rm -f *.o *~
[370user14@nostromo ex2]$ ./baseprog
> Please type your name for thread 1
gurinder
> Please type your age for thread 1
> Please type your birth month for thread 1
> Please type your name for thread 2
> Please type your age for thread 2
> Please type your birth month for thread 2
> Please type your birth year for thread 2
> Please type your birth year for thread 1
Finished
这是更正后的代码,修复了对scanf()的调用,消除了混乱,包括适当的错误检查,公理每行只有一个语句,(最多)每个语句后面有一个变量声明,并合并了其他注释。
#include <stdio.h>
#include <stdlib.h> // exit(), EXIT_FAILURE
#include <pthread.h> // pthread_*()
//#include <semaphore.h>
//#include <sched.h>
//#include <unistd.h>
//#include <signal.h>
//#include <sys/types.h>
//#include <string.h>
pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
typedef struct compound
{
char name [1024];
int age;
int birthMonth;
int birthYear;
int threadNumber;
} compound;
void * threadName (void * param)
{
compound *lparam = (compound *) param;
pthread_mutex_lock(&mutex);
printf ("> Please type your name for thread %dn", lparam->threadNumber);
scanf ("%1023s", lparam->name);
pthread_mutex_unlock(&mutex);
pthread_mutex_lock(&mutex);
printf ("> Please type your age for thread %dn", lparam->threadNumber);
scanf ("%d", &(lparam->age));
pthread_mutex_unlock(&mutex);
pthread_mutex_lock(&mutex);
printf ("> Please type the number of your birth month for thread %d (January=1)n", lparam->threadNumber);
scanf ("%d", &(lparam->birthMonth));
pthread_mutex_unlock(&mutex);
pthread_mutex_lock(&mutex);
printf ("> Please type your birth year for thread %dn", lparam->threadNumber);
scanf ("%d", &(lparam->birthYear));
pthread_mutex_unlock(&mutex);
pthread_exit( NULL );
} // end function: threadName
// main function
int main (void)
{
pthread_t thread_ID3;
pthread_t thread_ID4;
compound first;
compound second;
first.threadNumber= 1;
second.threadNumber = 2;
if( 0 != pthread_create (&thread_ID3, NULL, threadName, (void*)&first) )
{ // then pthread_create failed
perror( "pthread_create for first thread failed");
exit( EXIT_FAILURE );
}
// implied else pthread_create successful
if( 0 != pthread_create (&thread_ID4, NULL, threadName, (void*)&second) )
{ // then pthread_create failed
perror( "pthread_create for second thread failed" );
exit( EXIT_FAILURE );
}
// implied else pthread_create successful
pthread_join (thread_ID3, NULL);
pthread_join (thread_ID4, NULL);
printf("Finishedn");
int ch;
while( (ch = getchar()) != EOF && 'n' != ch );
getchar(); // wait for user to enter a final keystroke
return 0;
} // end function: main