Creación de Semáforos en C

Programa en Lenguaje C que manipula dos Semáforos. En breve lo comentare.

#include <stdio.h>

#include <stdlib.h>

#include <sys/types.h>

#include <sys/ipc.h>

#include <sys/sem.h>

#define SEM_HIJO 0

#define SEM_PADRE 1

main (int argc, int *argv[]) {

int i = 10, semid, pid;

struct sembuf opera;

key_t llave;

llave = ftok ( argv[0], ‘K’ );

if ( ( semid = semget ( llave, 2, IPC_CREAT | 0666 ) ) == -1 ) {

perror ( “semget” );

exit ( -1 );

}

// Cerrar el Semaforo del Hijo

semctl ( semid, SEM_PADRE, SETVAL, 0 );

// Abrir el Semaforo del Padre

semctl ( semid, SEM_PADRE, SETVAL, 1 );

if ( ( pid = fork () ) == -1 ) {

perror ( “fork “);

exit ( -1 );

}

else if ( pid == 0 ) {

while ( i ) {

opera.sem_num = SEM_HIJO;

opera.sem_op = -1;

opera.sem_flg = 0;

semop (semid, &opera, 1);

printf ( “Proceso Hijo: %d\n “, i– );

opera.sem_num = SEM_PADRE;

opera.sem_op = 1;

semop ( semid, &opera, 1 );

}

semctl ( semid, 0, IPC_RMID, 0 );

}

else {

opera.sem_flg = 0;

while ( i ) {

opera.sem_num = SEM_PADRE;

opera.sem_op = -1;

semop ( semid, &opera, 1 );

printf ( “Proceso Padre: %d\n “, i– );

opera.sem_num = SEM_HIJO;

opera.sem_op = 1;

semop ( semid, &opera, 1 );

}

semctl ( semid, 0, IPC_RMID, 0 );

}

}

#include <stdio.h>

#include <stdlib.h>

#include <sys/types.h>

#include <sys/ipc.h>

#include <sys/sem.h>

#define SEM_HIJO 0

#define SEM_PADRE 1

main (int argc, int *argv[]) {

int i = 10, semid, pid;

struct sembuf opera;

key_t llave;

llave = ftok ( argv[0], ‘K’ );

if ( ( semid = semget ( llave, 2, IPC_CREAT | 0666 ) ) == -1 ) {

perror ( “semget” );

exit ( -1 );

}

// Cerrar el Semaforo del Hijo

semctl ( semid, SEM_PADRE, SETVAL, 0 );

// Abrir el Semaforo del Padre

semctl ( semid, SEM_PADRE, SETVAL, 1 );

if ( ( pid = fork () ) == -1 ) {

perror ( “fork “);

exit ( -1 );

}

else if ( pid == 0 ) {

while ( i ) {

opera.sem_num = SEM_HIJO;

opera.sem_op = -1;

opera.sem_flg = 0;

semop (semid, &opera, 1);

printf ( “Proceso Hijo: %d\n “, i– );

opera.sem_num = SEM_PADRE;

opera.sem_op = 1;

semop ( semid, &opera, 1 );

}

semctl ( semid, 0, IPC_RMID, 0 );

}

else {

opera.sem_flg = 0;

while ( i ) {

opera.sem_num = SEM_PADRE;

opera.sem_op = -1;

semop ( semid, &opera, 1 );

printf ( “Proceso Padre: %d\n “, i– );

opera.sem_num = SEM_HIJO;

opera.sem_op = 1;

semop ( semid, &opera, 1 );

}

semctl ( semid, 0, IPC_RMID, 0 );

}#include <stdio.h>

#include <stdlib.h>

#include <sys/types.h>

#include <sys/ipc.h>

#include <sys/sem.h>

#define SEM_HIJO 0

#define SEM_PADRE 1

main (int argc, int *argv[]) {

int i = 10, semid, pid;

struct sembuf opera;

key_t llave;

llave = ftok ( argv[0], ‘K’ );

if ( ( semid = semget ( llave, 2, IPC_CREAT | 0666 ) ) == -1 ) {

perror ( “semget” );

exit ( -1 );

}

// Cerrar el Semaforo del Hijo

semctl ( semid, SEM_PADRE, SETVAL, 0 );

// Abrir el Semaforo del Padre

semctl ( semid, SEM_PADRE, SETVAL, 1 );

if ( ( pid = fork () ) == -1 ) {

perror ( “fork “);

exit ( -1 );

}

else if ( pid == 0 ) {

while ( i ) {

opera.sem_num = SEM_HIJO;

opera.sem_op = -1;

opera.sem_flg = 0;

semop (semid, &opera, 1);

printf ( “Proceso Hijo: %d\n “, i– );

opera.sem_num = SEM_PADRE;

opera.sem_op = 1;

semop ( semid, &opera, 1 );

}

semctl ( semid, 0, IPC_RMID, 0 );

}

else {

opera.sem_flg = 0;

while ( i ) {

opera.sem_num = SEM_PADRE;

opera.sem_op = -1;

semop ( semid, &opera, 1 );

printf ( “Proceso Padre: %d\n “, i– );

opera.sem_num = SEM_HIJO;

opera.sem_op = 1;

semop ( semid, &opera, 1 );

}

semctl ( semid, 0, IPC_RMID, 0 );

}

}

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