pthread mutex not working

[zak100]

Hi,
I have created a C programusing pthread.
[Code]
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h> //Header file for sleep(). man 3 sleep for details.
#include <pthread.h>

// A normal C function that is executed as a thread
// when its name is specified in pthread_create()

pthread_mutex_t lock;

void *myThreadFun1(void *vargp)
{

pthread_mutex_lock(&lock);
int i=0;
for(i=0;i<200;i++)
printf ("i=%d",i);
pthread_mutex_unlock(&lock);


}
void *myThreadFun2(void *vargp){
int j=0;
for(j=0; j<200; j++)
printf("j=%d", j);
}


int main()
{
pthread_t thread_id;
printf("Before Thread\n");
if(pthread_mutex_init(&lock, NULL) !=0){
printf("Mutex failed");
return -1;
}
pthread_create(&thread_id, NULL, myThreadFun1, NULL);
pthread_create(&thread_id, NULL, myThreadFun2, NULL);
pthread_join(thread_id, NULL);
printf("After Thread\n");
pthread_join(thread_id, NULL);
pthread_join(thread_id,NULL);
pthread_mutex_destroy(&lock);
}
[/code]

I have created two threads. Each thread is supposed to run a different function. In my myThreadFun1, I have created a lock so that its output should not interleave with the output of myThreadFun2. But the program is displaying following interleaved output:

$ ./a.out
Before Thread
i=0i=1i=2i=3i=4i=5i=6i=7i=8i=9i=10i=11i=12i=13i=14i=15i=16i=17i=18i=19i=20i=21i=22i=23i=24i=25i=26i=27i=28i=29i=30i=31i=32i=33i=34i=35i=36i=37i=38i=39i=40i=41i=42i=43i=44i=45i=46i=47i=48i=49i=50i=51i=52i=53i=54i=55i=56i=57i=58i=59i=60i=61i=62i=63i=64i=65i=66i=67i=68i=69i=70i=71i=72i=73i=74i=75i=76i=77i=78i=79j=0i=80j=1j=2i=81j=3i=82j=4i=83j=5i=84i=85i=86i=87j=6i=88j=7i=89j=8i=90j=9i=91j=10i=92j=11j=12j=13i=93j=14i=94j=15i=95j=16i=96j=17i=97j=18i=98i=99i=100j=19i=101j=20i=102i=103i=104i=105j=21i=106j=22j=23i=107j=24i=108i=109i=110i=111j=25i=112j=26i=113j=27i=114j=28i=115j=29i=116j=30j=31i=117i=118j=32i=119j=33i=120j=34i=121i=122i=123i=124j=35i=125i=126j=36i=127j=37i=128i=129i=130i=131i=132j=38i=133j=39i=134j=40i=135i=136i=137i=138j=41i=139j=42i=140j=43i=141j=44i=142i=143i=144i=145i=146j=45i=147j=46j=47i=148j=48i=149j=49i=150j=50i=151i=152i=153i=154j=51i=155j=52i=156j=53i=157j=54j=55i=158j=56i=159j=57j=58i=160j=59i=161j=60i=162i=163i=164i=165i=166j=61i=167j=62i=168j=63i=169i=170i=171i=172i=173j=64i=174j=65i=175i=176i=177i=178i=179i=180i=181i=182i=183i=184i=185i=186i=187i=188i=189i=190i=191i=192i=193i=194i=195i=196i=197i=198i=199j=66j=67j=68j=69j=70j=71j=72j=73j=74j=75j=76j=77j=78j=79j=80j=81j=82j=83j=84j=85j=86j=87j=88j=89j=90j=91j=92j=93j=94j=95j=96j=97j=98j=99j=100j=101j=102j=103j=104j=105j=106j=107j=108j=109j=110j=111j=112j=113j=114j=115j=116j=117j=118j=119j=120j=121j=122j=123j=124j=125j=126j=127j=128j=129j=130j=131j=132j=133j=134j=135j=136j=137j=138j=139j=140j=141j=142j=143j=144j=145j=146j=147j=148j=149j=150j=151j=152j=153j=154j=155j=156j=157j=158j=159j=160j=161j=162j=163j=164j=165j=166j=167j=168j=169j=170j=171j=172j=173j=174j=175j=176j=177j=178j=179j=180j=181j=182j=183j=184j=185j=186j=187j=188j=189j=190j=191j=192j=193j=194j=195j=196j=197j=198j=199After Thread





Somebody please guide me how to solv this problem.

Zulfi.

[salem c]

1. It's [code][/code], not <code></code> (despite the misleading shape on the icons).

2. You NEED the mutex in myThreadFun2 as well.

[zak100]

Hi,
Thanks.

It worked.

God bless you.

Zulfi.

[shivkumar12]

Hi your code is not correct which is define below:

pthread_create(&thread_id, NULL, myThreadFun1, NULL);


pthread_mutex_t lock;

void *myThreadFun1(void *vargp)
{

pthread_mutex_lock(&lock);
int i=0;
for(i=0;i<200;i++)
printf ("i=%d",i);
pthread_mutex_unlock(&lock);


}
void *myThreadFun2(void *vargp){
int j=0;
for(j=0; j<200; j++)
printf("j=%d", j);
}


int main()
{
pthread_t thread_id;
printf("Before Thread\n");
if(pthread_mutex_init(&lock, NULL) !=0){
printf("Mutex failed");
return -1;
}
pthread_create(&thread_id, NULL, myThreadFun1, NULL);
pthread_create(&thread_id, NULL, myThreadFun2, NULL);
pthread_join(thread_id, NULL);
printf("After Thread\n");
pthread_join(thread_id, NULL);
pthread_join(thread_id,NULL);
pthread_mutex_destroy(&lock);
}
[/code]

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