c语言操作大于2G文本

1.源码实现

#define _FILE_OFFSET_BITS 64

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

int main()
{
    FILE *fp = NULL;
    char buf[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz ,,./?\\()*&^%$#@!~`\"{}[]|<>";
    char tmp[1024*1024];
    int a = 0;
    int i, j, k;
    int len = strlen(buf);

    srand((unsigned)time(NULL));

    fp = fopen("1.txt", "wb");
    if(fp == NULL)
    {
        return -1;
    }

    for(k=0; k<6144; k++)
    //for(k=0; k<1024; k++)
    {
        for(j=0; j<1024; j++)
        {
            for(i=0; i<1023; i++)
            {
                a = rand() % len;
                tmp[1024*j+i] = buf[a];
            }

            tmp[1024*j+i] = '\n';
        }

        fwrite(tmp, 1024*1024, 1, fp);
    }

    fclose(fp);

    return 0;
}

2.编译源码

$ gcc -o example example.c

3.运行及其结果

$ time ./example
real    2m3.855s
user    1m48.128s
sys 0m5.541s