How can I "convert" 2 processes to a parent-child process? - c

Question

So I've got this great code for a C example of a deadlock by Ali Hasan Ahmed Khan previously. I was just thinking about converting it to a parent-child process, so somehow making funcA the parent, then forking funcB. When I used the fork command, I was met with an error in main, saying funcB is non existent. Can this be converted? The full code is:
#include <stdio.h>
#include <unistd.h>
#include <pthread.h>
#include <sys/sem.h>
#define PERMS 0660
int semId;
int initSem(int semId, int semNum, int initValue) {
return semctl(semId, semNum, SETVAL, initValue);
}
// Try to take a resource, wait if not available
int P(int semId, int semNum) {
struct sembuf operationList[1];
operationList[0].sem_num = semNum;
operationList[0].sem_op = -1;
operationList[0].sem_flg = 0;
return semop(semId, operationList, 1);
}
// Release a resource
int V(int semId, int semNum) {
struct sembuf operationList[1];
operationList[0].sem_num = semNum;
operationList[0].sem_op = 1;
operationList[0].sem_flg = 0;
return semop(semId, operationList, 1);
}
void* funcA(void* nothing) {
printf("Thread A try to lock 0...\n");
P(semId, 0); // Take resource/semaphore 0 of semID
printf("Thread A locked 0.\n");
usleep(50*1000); // Wait 50 ms
printf("Thread A try to lock 1...\n");
P(semId, 1); // Take resource/semaphore 1 of semID
printf("Thread A locked 1.\n");
V(semId, 0); // Release resource/semaphore 0 of semID
V(semId, 1); // Release resource/semaphore 1 of semID
return NULL;
}
void* funcB(void* nothing) {
printf("Thread B try to lock 1...\n");
P(semId, 1);
printf("Thread B locked 1.\n");
usleep(5*1000);
printf("Thread B try to lock 0...\n");
P(semId, 0);
printf("Thread B locked 0.\n");
V(semId, 0);
V(semId, 1);
return NULL;
}
int main(int argc, char* argv[]) {
int i;
// ftok generates a key based on the program name and a char value
semId = semget(ftok(argv[0], 'A'), 2, IPC_CREAT | PERMS);
initSem(semId, 0, 1);
initSem(semId, 1, 1);
pthread_t thread[2];
pthread_create(&thread[0], NULL, funcA, NULL);
pthread_create(&thread[1], NULL, funcB, NULL);
for (i = 0 ; i < 2 ; i++) {
pthread_join(thread[i], NULL);
}
printf("This is not printed in case of deadlock\n");
semctl(semId, 0, IPC_RMID, 0);
semctl(semId, 1, IPC_RMID, 0);
return 0;
}