标签：des style class blog code http
存储映射I/O使一个磁盘文件与存储空间中的一个缓冲区相映射，对缓冲区的读、写操作就是对文件的读、写操作，从而可以不再使用read、write系统调用。#include <sys/mman.h> /* 成功返回映射区起始地址，出错返回MAP_FAILED */ void *mmap(void *addr, size_t len, int prot, int flag, int filedes, off_t off);
#include <stdio.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <string.h>
#define FILE_MODE (S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH)
int main(int argc, char *argv[])
{
int fdin, fdout;
void *src, *dst;
struct stat statbuf;
if (argc != 3)
{
printf("usage: %s <fromfile> <tofile>\n", argv[0]);
return -1;
}
fdin = open(argv[1], O_RDONLY);
fdout = open(argv[2], O_RDWR | O_CREAT | O_TRUNC, FILE_MODE);
fstat(fdin, &statbuf);
lseek(fdout, statbuf.st_size - 1, SEEK_SET);
write(fdout, " ", 1); /* lseek偏移量大于文件长度时，写操作将加长文件 */
src = mmap(0, statbuf.st_size, PROT_READ, MAP_SHARED, fdin, 0);
dst = mmap(0, statbuf.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, fdout, 0);
memcpy(dst, src, statbuf.st_size); /* 数据复制 */
munmap(src, statbuf.st_size);
munmap(dst, statbuf.st_size);
return 0;
}【Linux编程】存储映射I/O,布布扣,bubuko.com
标签：des style class blog code http
原文地址：http://blog.csdn.net/nestler/article/details/32914179
