C语言多线程拷贝文件

以下是一个使用C语言多线程拷贝文件的例子：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>

#define BUFFER_SIZE 1024

struct copy_args {
    char *src_file;
    char *dst_file;
    int start_pos;
    int end_pos;
};

void *copy_file(void *arg) {
    struct copy_args *args = (struct copy_args *)arg;
    FILE *src_fp = fopen(args->src_file, "rb");
    FILE *dst_fp = fopen(args->dst_file, "wb");
    if (src_fp == NULL || dst_fp == NULL) {
        printf("Failed to open file.\n");
        exit(1);
    }
    fseek(src_fp, args->start_pos, SEEK_SET);
    int len = args->end_pos - args->start_pos + 1;
    char buffer[BUFFER_SIZE];
    int read_len, write_len;
    while (len > 0 && (read_len = fread(buffer, 1, BUFFER_SIZE, src_fp)) > 0) {
        if (read_len > len) {
            read_len = len;
        }
        write_len = fwrite(buffer, 1, read_len, dst_fp);
        if (write_len != read_len) {
            printf("Failed to write file.\n");
            exit(1);
        }
        len -= read_len;
    }
    fclose(src_fp);
    fclose(dst_fp);
    return NULL;
}

void multi_thread_copy(char *src_file, char *dst_file, int thread_num) {
    FILE *fp = fopen(src_file, "rb");
    if (fp == NULL) {
        printf("Failed to open file.\n");
        exit(1);
    }
    fseek(fp, 0, SEEK_END);
    int file_size = ftell(fp);
    fclose(fp);
    int block_size = file_size / thread_num;
    pthread_t *threads = (pthread_t *)malloc(thread_num * sizeof(pthread_t));
    struct copy_args *args = (struct copy_args *)malloc(thread_num * sizeof(struct copy_args));
    for (int i = 0; i < thread_num; i++) {
        args[i].src_file = src_file;
        args[i].dst_file = dst_file;
        args[i].start_pos = i * block_size;        if (i == thread_num - 1) {
            args[i].end_pos = file_size - 1;
        } else {
            args[i].end_pos = (i + 1) * block_size - 1;
        }
        pthread_create(&threads[i], NULL, copy_file, &args[i]);
    }
    for (int i = 0; i < thread_num; i++) {
        pthread_join(threads[i], NULL);
    }
    free(threads);
    free(args);
}

int main() {
    char *src_file = "/home/XXX";
    char *dst_file = "/home/dir/XXX";
    int thread_num = 4;
    multi_thread_copy(src_file, dst_file, thread_num);
    printf("Copy file finished.\n");
    return 0;
}