Issues with pthread in C - c

Question

I have a problem with the compiling of my program, when I test something like "./philo -p 3 -e 4" I get the error
philo: tpp.c:62: __pthread_tpp_change_priority: Assertion `new_prio == -1 || (new_prio >= __sched_fifo_min_prio && new_prio <= __sched_fifo_max_prio)' failed.
Aborted
But I don't understand where it does come from, as it's working sometimes, for exemple if I test "./philo -p 2 -e 4" it doesn't crash.
The two .h
#ifndef _PHILO_H_
# define _PHILO_H_
#include <pthread.h>
typedef struct s_philosop
{
pthread_t philosophers;
pthread_mutex_t *chopsticks1;
pthread_mutex_t *chopsticks2;
int nbr_occ;
} t_philosop;
int parse_arg(char **argv, int *philo, int *occ);
int create_threads_mutex(int nbr_philo, int occurences);
void *start_routine(void *arg);
void philosoph_eating_chopsticks(t_philosop *philosop);
#endif /* !_PHILO_H_ */
#ifndef __LIBRICEFEREE_EXTERN__
# define __LIBRICEFEREE_EXTERN__
#include <pthread.h>
int RCFStartup(int ac, char **av);
void RCFCleanup();
int lphilo_eat();
int lphilo_sleep();
int lphilo_think();
int lphilo_take_chopstick(const pthread_mutex_t *mutex_id);
int lphilo_release_chopstick(const pthread_mutex_t *mutex_id);
#endif /* __LIBRICEFEREE_EXTERN__ */
And this is my .c
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <pthread.h>
#include <unistd.h>
#include "philo.h"
#include "extern.h"
void philosoph_comportement(t_philosop *philosop)
{
int i = 0;
if ((pthread_mutex_lock(philosop->chopsticks1)) == 0)
{
printf("%s\n", "Taking left stick");
lphilo_take_chopstick(philosop->chopsticks1);
i++;
}
if ((pthread_mutex_lock(philosop->chopsticks2)) == 0)
{
printf("%s\n", "Taking right stick");
lphilo_take_chopstick(philosop->chopsticks2);
i++;
}
if (i == 2)
{
printf("%s\n", "Eat");
lphilo_eat();
sleep(1);
printf("%s\n", "Sleep");
pthread_mutex_unlock(philosop->chopsticks1);
pthread_mutex_unlock(philosop->chopsticks2);
lphilo_release_chopstick(philosop->chopsticks1);
lphilo_release_chopstick(philosop->chopsticks2);
lphilo_sleep();
}
}
void *start_routine(void *arg)
{
t_philosop *philosop;
int i;
i = 0;
philosop = (t_philosop *)arg;
while (i != philosop->nbr_occ)
{
philosoph_comportement(philosop);
i++;
}
return (0);
}
int create_threads_mutex(int nbr_philo, int occurences)
{
int i;
t_philosop *philosop;
pthread_mutex_t *chopsticks;
i = -1;
if ((chopsticks = malloc(sizeof(pthread_mutex_t) * nbr_philo)) == NULL)
return (2);
if ((philosop = malloc(sizeof(t_philosop) * nbr_philo)) == NULL)
return (2);
while (++i != nbr_philo)
{
philosop[i].nbr_occ = occurences;
philosop[i].chopsticks1 = &chopsticks[i];
if (i - 1 < 0)
philosop[i].chopsticks2 = &chopsticks[nbr_philo];
else
philosop[i].chopsticks2 = &chopsticks[i - 1];
}
i = -1;
while (++i != nbr_philo)
pthread_create(&philosop[i].philosophers, NULL, start_routine, &philosop[i]);
i = -1;
while (++i != nbr_philo)
{
printf("Philo number : %d\n", i);
pthread_join(philosop[i].philosophers, NULL);
}
return (0);
}
int parse_arg(char **argv, int *philo, int *occ)
{
if (strcmp(argv[1], "-p") == 0 && strcmp(argv[3], "-e") == 0 &&
argv[2] != NULL && argv[4] != NULL)
{
*philo = atoi(argv[2]);
*occ = atoi(argv[4]);
}
else if (strcmp(argv[1], "-e") == 0 && strcmp(argv[3], "-p") == 0 &&
argv[2] != NULL && argv[4] != NULL)
{
*philo = atoi(argv[4]);
*occ = atoi(argv[2]);
}
else
return (2);
return (0);
}
int main(int argc, char **argv)
{
int philo;
int occurences;
philo = 0;
occurences = 0;
if (argc != 5)
return (2);
if ((parse_arg(argv, &philo, &occurences)) == 2)
return (2);
RCFStartup(argc, argv);
if ((create_threads_mutex(philo, occurences)) == 2)
return (2);
RCFCleanup();
return (0);
}

Answer 1

You don't initialize any of your mutexes with pthread_mutex_init.
And assuming lphilo_release_chopstick does nothing but unlock a mutex, this code is wrong as it will try to unlock each mutex twice:
pthread_mutex_unlock(philosop->chopsticks1);
pthread_mutex_unlock(philosop->chopsticks2);
lphilo_release_chopstick(philosop->chopsticks1);
lphilo_release_chopstick(philosop->chopsticks2);