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Synchronization of threads C. Error: Expected ')' before ';'

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# 1  
Old 11-10-2011
Synchronization of threads C. Error: Expected ')' before ';'
Hi,

I'm trying to solve an assignement on school where we are supposed to synchronize two threads and write out their ID every other time.

I've written down the code for the two threadFunctions which is associated with two threads created in the main function.

What I'm trying to achieve here is that thread 1 will check if count is an even number. If so then it prints out and adds 1 to count and then signals thread 2 to take over.

But I get error when compiling:

In function threadFunction1: error: expected ')' before ';' token
In function threadFunction2: error: expected ')' before ';' token
one the lines where the while loop is written. Anybody know why?

Code:
#include <unistd.h>
#include <stdio.h>
#include <pthread.h>

#define COUNT_MAX 20;

pthread_mutex_t laas1;
pthread_mutex_t laas2;
pthread_cond_t cond_var;
int count = 0;

void *threadFunction1() {
pthread_mutex_lock(&laas1);
while(count<COUNT_MAX) {
if((count & 1) == 0) {
printf("Printout %d for thread 1:\t TID: %ld\n", count+1, pthread_self());
count++;
pthread_cond_signal(&cond_var);
}//if
}//while
pthread_mutex_unlock(&laas1);
return NULL;
}//threadFunction1

void *threadFunction2() {
while(count<COUNT_MAX) {
pthread_mutex_lock(&laas2);
pthread_cond_wait(&cond_var, &laas1);
printf("Printout %d for thread 2:\t TID: %ld\n", count, pthread_self());
count++;
pthread_mutex_unlock(&laas2);
}//while
return NULL;
}//threadFunction2

# 2  
Old 11-10-2011
Are you missing the PTHREAD_MUTEX_INITIALIZER ?

Code:
 
pthread_mutex_t laas1 = PTHREAD_MUTEX_INITIALIZER;
pthread_mutex_t laas2 = PTHREAD_MUTEX_INITIALIZER;

Linux Tutorial: POSIX Threads
# 3  
Old 11-10-2011
in the main function I've done it like this:

pthread_mutex_init(&laas1, NULL);
pthread_mutex_init(&laas2, NULL);
# 4  
Old 11-10-2011
This is your error:

Code:
 #define COUNT_MAX 20;

Remove the semicolon. It gets expanded to this:

Code:
while(count<20;)

# 5  
Old 11-10-2011
Quote:
Originally Posted by sjallamander
Hi,

I'm trying to solve an assignement on school where we are supposed to synchronize two threads and write out their ID every other time.

I've written down the code for the two threadFunctions which is associated with two threads created in the main function.

What I'm trying to achieve here is that thread 1 will check if count is an even number. If so then it prints out and adds 1 to count and then signals thread 2 to take over.

But I get error when compiling:

In function threadFunction1: error: expected ')' before ';' token
In function threadFunction2: error: expected ')' before ';' token
one the lines where the while loop is written. Anybody know why?

Code:
#include <unistd.h>
#include <stdio.h>
#include <pthread.h>

#define COUNT_MAX 20;

pthread_mutex_t laas1;
pthread_mutex_t laas2;
pthread_cond_t cond_var;
int count = 0;

void *threadFunction1() {
pthread_mutex_lock(&laas1);
while(count<COUNT_MAX) {
if((count & 1) == 0) {
printf("Printout %d for thread 1:\t TID: %ld\n", count+1, pthread_self());
count++;
pthread_cond_signal(&cond_var);
}//if
}//while
pthread_mutex_unlock(&laas1);
return NULL;
}//threadFunction1

void *threadFunction2() {
while(count<COUNT_MAX) {
pthread_mutex_lock(&laas2);
pthread_cond_wait(&cond_var, &laas1);
printf("Printout %d for thread 2:\t TID: %ld\n", count, pthread_self());
count++;
pthread_mutex_unlock(&laas2);
}//while
return NULL;
}//threadFunction2

your error is

#define COUNT_MAX 20; should be #define COUNT_MAX 20
# 6  
Old 11-14-2011
doh :S...thank youSmilie
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