Programming

how to do with that?

after cc -o xxxx xxxx.c



ld:
Unresolved:
_pthread_create
_pthread_deteach
_pthread_exit


Thanks

Code:

cc -o xxxx xxxx.c -lpthread

I want to print '*' and '0'. But after executing the program , no any response.
Whoud you please look at my codes, it's simple. However it is my first coding in unix enviroment. I am not stong in C++. I think something wrong.

#include<pthread.h>
#include<stdio.h>
int num_pthreads = 2;

void *PrintStar(void *arg)
{
int i,count,row;

for (count = 1,row =1;row<11; row++,count++)
{
for (i = 0; i < count; i++)
{
printf("*");
fflush(NULL);
sleep(1);
}
printf("\n");
sleep(1);
}
return NULL;
}

void *PrintNum(void *arg)
{
int i, count, row;

for(count = 1,row = 1; row<11; row++, count++)
{
for (i = 0; i<count; i++)
{
printf("0");
fflush(NULL);
sleep(1);
}
printf("\n");
sleep(1);
}
return NULL;
}

/********* this is the main thread's code */
int main()
{
pthread_t thread; /* holds thread info */
int i;

/* create the threads */
for (i = 0; i<num_pthreads;i++)
{
if(pthread_create(&thread,NULL,PrintStar,NULL))
printf("error creating a new thread PrintStar \n");
exit(1);
}
pthread_detach(thread);


for (i = 0; i<num_pthreads;i++)
{
if(pthread_create(&thread,NULL,PrintNum,NULL))
printf("error creating a new thread PrintNum \n");
exit(1);
}
pthread_detach(thread);

pthread_exit(NULL);
}

for (i = 0; i<num_pthreads;i++)
{
if(pthread_create(&thread,NULL,PrintStar,NULL))
printf("error creating a new thread PrintStar \n");
exit(1);
}
pthread_detach(thread);

why is that exit there ?
I suppose you want to put it in the if block !! Something like this, ( note the additional braces after the if and efter the exit statement.

for (i = 0; i<num_pthreads;i++)
{
if(pthread_create(&thread,NULL,PrintStar,NULL)) {
printf("error creating a new thread PrintStar \n");
exit(1);
}
}
pthread_detach(thread);