和菜鸟一起深入学习国嵌实验之线程编程

1、 线程创建

代码：

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <errno.h>
#include <math.h>
#include <pthread.h>
 
struct member
{
   int a;
   char *s;
};
 
void *create(void *arg)
{
   struct member *temp;
  
   temp = (struct member *)arg;
   printf("member->a : %d\n", temp->a);
   printf("member->s : %s\n", temp->s);
  
   return (void*)0;
}
 
int main(int argc, char *argv[])
{
   int error;
   pthread_t tidp;
   struct member *b;
 
    b= (struct member *)malloc(sizeof(struct member));
   b->a = 4;
   b->s = "eastmoon";
 
   error = pthread_create(&tidp, NULL, create, (void*)b);
   if(error)
    {
       printf("pthread is not create...\n");
        return -1;
    }
   
   sleep(1);
   printf("pthread is created...\n");
 
   return 0;
}

Makefile:

CC = gcc
 
CURTDIR = $(shell pwd)
TARGET = mythread
 
%.o:%.c
       $(CC)-c $(EXTRAFLAGS) $< -o $@
%.o:%.S
       $(CC)-c $(EXTRAFLAGS) $< -o $@
 
.PHONY: all clean
 
$(TARGET): $(TARGET).o
       $(CC)  -o $@ $^ -lpthread
 
clean:
       rm-rf $(TARGET) $(TARGET).o

运行结果：

eastmoon@eastmoon-virtual-machine:~/work/guoqian/3/3.1$ make
gcc -c  mythread.c -o mythread.o
gcc  -o mythread mythread.o -lpthread

eastmoon@eastmoon-virtual-machine:~/work/guoqian/3/3.1$ ls
Makefile  mypipe.txt  mythread  mythread.c  mythread.o

eastmoon@eastmoon-virtual-machine:~/work/guoqian/3/3.1$ ./mythread 
member->a : 4
member->s : eastmoon
pthread is created...

2、 线程等待

代码：

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <errno.h>
#include <math.h>
#include <pthread.h>
 
void *create(void *arg)
{  
   int i;
   
   for(i = 0; i < 3; i++)
    {
       sleep(2);
       printf("This in the thread :%d\n", i);
    }
   
   return NULL;
}
 
int main(int argc, char *argv[])
{
   pthread_t pth;
   int i, ret;
 
   ret = pthread_create(&pth, NULL, create, NULL);
   if(ret)
    {
       printf("pthread is not create...\n");
       return -1;
    }
  
   pthread_join(pth, NULL);
 
   printf("thread was exit\n");
  
   for(i = 0; i < 3; i++)
    {
       sleep(1);
       printf("This in the main: %d\n", i);
    }
 
   return 0;
}

Makefile：

CC = gcc



CURTDIR = $(shell pwd)

TARGET = mythread_join



%.o:%.c

$(CC)-c $(EXTRAFLAGS) $< -o $@

%.o:%.S

$(CC)-c $(EXTRAFLAGS) $< -o $@



.PHONY: all clean



$(TARGET): $(TARGET).o

$(CC) -o $@ $^ -lpthread



clean:

rm-rf $(TARGET) $(TARGET).o



运行结果：

eastmoon@eastmoon-virtual-machine:~/work/guoqian/3/3.2$make
gcc -c mythread_join.c -o mythread_join.o
gcc -o mythread_join mythread_join.o -lpthread
 
eastmoon@eastmoon-virtual-machine:~/work/guoqian/3/3.2$ls
Makefile mythread_join mythread_join.c  mythread_join.o
 
eastmoon@eastmoon-virtual-machine:~/work/guoqian/3/3.2$./mythread_join
This in the thread :0
This in the thread :1
This in the thread :2
thread was exit
This in the main: 0
This in the main: 1
This in the main: 2

总结：运行程序后，在没有调用thread_join之前线程和进程是同时运行的，调用了thread_join之后进程阻塞直到线程退出。



3、 线程退出保护设计

代码:

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <errno.h>
#include <math.h>
#include <pthread.h>
 
void *clean(void *arg)
{  
   printf("cleanup: %s\n", (char *)arg);
   
   return (void *)0;
   
}
 
void *thr_fn1(void *arg)
{
   printf("thread 1 start \n");
   
   pthread_cleanup_push((void *)clean, "thread 1 first handler");
   pthread_cleanup_push((void *)clean, "thread 1 secondhandler");
   
   printf("thread 1 push complete\n");
 
   if(arg)
    {
       return (void*)1;
    }
 
   pthread_cleanup_pop(0);
   pthread_cleanup_pop(0);
 
   return (void *)1;
 
}
 
void *thr_fn2(void *arg)
{
   printf("thread 2 start \n");
   
   pthread_cleanup_push((void *)clean, "thread 2 first handler");
   pthread_cleanup_push((void *)clean, "thread 2 secondhandler");
   
   printf("thread 2 push complete\n");
 
   if(arg)
    {
       pthread_exit((void *)2);
    }
 
   pthread_cleanup_pop(0);
   pthread_cleanup_pop(0);
 
   pthread_exit((void *)2);
 
}
int main(int argc, char *argv[])
{
   pthread_t tid1, tid2;
   int i, ret;
   void *tret;
 
   ret = pthread_create(&tid1, NULL, thr_fn1, (void *)1);
   if(ret)
    {
       printf("pthread 1 is not create...\n");
       return -1;
    }
  
   ret = pthread_create(&tid2, NULL, thr_fn2, (void *)1);
   if(ret)
    {
       printf("pthread 2 is not create...\n");
       return -1;
    }
  
   ret = pthread_join(tid1, &tret);
   if(ret)
    {
       printf("pthread 1 join error......\n");
       return -1;
    }
 
   printf("thread 1 exit code %d\n", (int)tret);
  
   ret = pthread_join(tid2, &tret);
   if(ret)
    {
       printf("pthread 2 join error......\n");
       return -1;
    }
 
   printf("thread 2 exit code %d\n", (int)tret);
  
   return 0;
}

Makefile：

CC = gcc
 
CURTDIR = $(shell pwd)
TARGET = mythread_clean
 
%.o:%.c
       $(CC)-c $(EXTRAFLAGS) $< -o $@
%.o:%.S
       $(CC)-c $(EXTRAFLAGS) $< -o $@
 
.PHONY: all clean
 
$(TARGET): $(TARGET).o
       $(CC)  -o $@ $^ -lpthread
 
clean:
       rm-rf $(TARGET) $(TARGET).o

运行结果：

eastmoon@eastmoon-virtual-machine:~/work/guoqian/3/3.3$make
gcc -c mythread_clean.c -o mythread_clean.o
gcc -o mythread_clean mythread_clean.o -lpthread
 
eastmoon@eastmoon-virtual-machine:~/work/guoqian/3/3.3$ls
Makefile mythread_clean mythread_clean.c  mythread_clean.o
 
eastmoon@eastmoon-virtual-machine:~/work/guoqian/3/3.3$./mythread_clean
thread 2 start
thread 2 push complete
cleanup: thread 2 second handler
cleanup: thread 2 first handler
thread 1 start
thread 1 push complete
thread 1 exit code 1
thread 2 exit code 2

总结：由运行结果可知，线程1是return退出的，所以不运行线程清理函数，而线程2是pthread_exit退出的，所以执行了线程清理函数。