Answer by Ajith C Narayanan for Pass variables to other functions in C

void outer_function(redisContext  *c, redisReply **reply) {
    *reply = redisCommand(c, "MY-REDIS-COMMAND");
    ...    
    return;
}

int main(int argc, char **argv) {
    ...
    redisContext *c;
    redisReply *reply;
    ...
    outer_function(c,&replay);
    return 0;
}