APUE学习笔记 文件和目录 显示文件大小

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
static off_t flen(FILE *fp)
{
        struct stat statres;
        if(fstat(fileno(fp), &statres) < 0)
        {
                return -1;
        }
        return statres.st_size;
}
int main(int argc, char **argv)
{
        FILE *fp;
        off_t len;
        if(argc < 2)
        {
                fprintf(stderr, "Usage...\n");
                exit(1);
        }
        fp = fopen(argv[1], "rb");
        if((fp == NULL))
        {
                return -1;
        }
        len = flen(fp);
        if(len < 0)
        {
                perror("flen()error");
                exit(1);
        }
        else
        {
                printf("%lld\n", (int64_t)len);
                fclose(fp);
                exit(0);
        }
}
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