Function setExpire

app/redis-6.2.6/src/db.c:1412–1424

Set an expire to the specified key. If the expire is set in the context * of an user calling a command 'c' is the client, otherwise 'c' is set * to NULL. The 'when' parameter is the absolute unix time in milliseconds * after which the key will no longer be considered valid. */

 * to NULL. The 'when' parameter is the absolute unix time in milliseconds
 * after which the key will no longer be considered valid. */
void setExpire(client *c, redisDb *db, robj *key, long long when) {
    dictEntry *kde, *de;

    /* Reuse the sds from the main dict in the expire dict */
    kde = dictFind(db->dict,key->ptr);
    serverAssertWithInfo(NULL,key,kde != NULL);
    de = dictAddOrFind(db->expires,dictGetKey(kde));
    dictSetSignedIntegerVal(de,when);

    int writable_slave = server.masterhost && server.repl_slave_ro == 0;
    if (c && writable_slave && !(c->flags & CLIENT_MASTER))
        rememberSlaveKeyWithExpire(db,key);
}

/* Return the expire time of the specified key, or -1 if no expire
 * is associated with this key (i.e. the key is non volatile) */