62 lines
1.3 KiB
C
62 lines
1.3 KiB
C
#include <sys/mman.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <stdlib.h>
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int main()
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{
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// 打开文件
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int fd = open("example.txt", O_RDWR | O_CREAT | O_TRUNC, 0777);
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if (fd == -1)
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{
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perror("open");
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exit(EXIT_FAILURE);
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}
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write(fd, "HelloWorld!", 11);
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char buf[12];
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buf[11] = '\0';
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close(fd);
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fd = open("example.txt", O_RDWR);
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read(fd, buf, 11);
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printf("File content: %s\n", buf);
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// 将文件映射到内存
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void *map = mmap(NULL, 11, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
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if (map == MAP_FAILED)
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{
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perror("mmap");
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close(fd);
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exit(EXIT_FAILURE);
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}
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printf("mmap address: %p\n", map);
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// 关闭文件描述符
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// close(fd);
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// 访问和修改文件内容
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char *fileContent = (char *)map;
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printf("change 'H' to 'G'\n");
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fileContent[0] = 'G'; // 修改第一个字符为 'G'
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printf("mmap content: %s\n", fileContent);
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// 解除映射
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printf("unmap\n");
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if (munmap(map, 11) == -1)
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{
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perror("munmap");
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exit(EXIT_FAILURE);
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}
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fd = open("example.txt", O_RDWR);
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read(fd, buf, 11);
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printf("File content: %s\n", buf);
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return 0;
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}
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