c++ - Synchronizing mutiple processes in C with shared memory -

i have program creates child processes in loop fork(). child create other processes well.

all processes must increment count, , count must displayed @ end.

to used simple locking system. shared memory of size 2. there 2 variable of type sig_tomic_t: count , lock.

when process wants increment count sets lock 1, increments count, sets lock 0. otherwise, if lock 1, process sleeps.

here code segment of interest.

for(i = 1; <= 10; i++) {      if((pid = fork()) < 0) {         perror("error fork!");         exit(2);     }      if(*lock == 0) {         *lock = 1;         *count = *count  + 1;         *lock = 0;     }     else {         while(*lock == 1) {             sleep(1);         }     }  } 

the problem though used simple locking system, count isn't incremented correctly.