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c++multithreadingpthreadspthread-join

PThread - Thread Exiting early despite calling pthread_join

I have implemented PThreads in a fairly elementary way as:

#include<iostream>
#include<pthread.h>
#include<stdio.h>

using namespace std;

class ThreadParameter
{
public:
char symbol_char;
int count;
};

void* print_char (void* param)
{

ThreadParameter* p = (ThreadParameter*)param;

for (int i=0; i< p->count; i++)
{
cout<< p->symbol_char <<endl;
i++;
}
return NULL;
}

int main ()
{
pthread_t thread1_id;

ThreadParameter param1;

param1.symbol_char = 'X';
param1.count = 27;

pthread_create (&thread1_id, NULL, &print_char, &param1);

int i = 0;

while (i<10)
{
cout<<"O"<<endl;
i++;
}

pthread_join(thread1_id,NULL);

return 0;
}

And its output is not showing the expected nos of X. Am I doing some mistake in calling join function or what? Thanks for help.

Output

P.S: I have tried various values of X from 5 to 20, but it always gives me lesser than the desired numbers of X.

Solution

  • You are incrementing i twice in print_char().

    Change 

    for (int i=0; i< p->count; i++)
{
    cout<< p->symbol_char <<endl;
    i++;
}

    into 

    for (int i=0; i< p->count; i++)
{
    cout<< p->symbol_char <<endl;
}