pthreads cnt lines

#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <string.h>
#include <sched.h>

#define LINE_SIZE (1 << 12)

static char target;
void *routine(void *arg) {
    char *line = (char*)arg;
    int cnt = 0;
    for (int i = 0; line[i]; i++) {
        if (line[i] == target) {
            cnt++;
        }
    }
    printf("cnt=%d\n", cnt);
    return NULL;
}

int main(int argc, char *argv[]) {
    if (argc != 2) {
        fprintf(stderr, "WRONG USAGE!\n");
        exit(1);
    }
    target = argv[1][0];

    cpu_set_t cpuset;
    CPU_ZERO(&cpuset);
    CPU_SET(0, &cpuset);

    pthread_attr_t attr;
    pthread_attr_init(&attr);
    pthread_attr_setaffinity_np(&attr, sizeof(cpu_set_t), &cpuset);

    char line[LINE_SIZE];
    while (fgets(line, LINE_SIZE, stdin)) {
        pthread_t thread;
        int r = 0;
        if ((r = pthread_create(&thread, &attr, routine, line)) != 0) {
            fprintf(stderr, "pthread_create: %s\n", strerror(r));
            exit(1);
        }

        if ((r = pthread_join(thread, NULL)) != 0) {
            fprintf(stderr, "pthread_join: %s\n", strerror(r));
            exit(1);
        }
    }
    pthread_attr_destroy(&attr);

    return 0;
}