linux read 返回值

ssize_t read(int fd, void *buf, size_t count);

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>

int main() {
    int fd = open("example.txt", O_RDONLY);
    if (fd == -1) {
        perror("open");
        return EXIT_FAILURE;
    }

    char buffer[1024];
    ssize_t bytes_read;

    while ((bytes_read = read(fd, buffer, sizeof(buffer))) > 0) {
        // 处理读取到的数据
        printf("Read %zd bytes: %.*s\n", bytes_read, (int)bytes_read, buffer);
    }

    if (bytes_read == -1) {
        perror("read");
    } else if (bytes_read == 0) {
        printf("End of file reached.\n");
    }

    close(fd);
    return EXIT_SUCCESS;
}