使用mmap記憶體對映實現一端寫，另一端讀的程序間通訊
寫端**write.c
/*write.c*/
#include #include #include #include #include #include #include /*對映記憶體大小*/ #define maplen 0x100 /*定義乙個學生資訊結構體*/ struct stu ; /*出錯資訊統一處理函式*/ void sys_err(char *str, int exitno) int main(int argc, char*ar**) fd = open(ar**[1], o_rdwr | o_creat, 0777); //開啟一檔案 if(fd < 0) if(lseek(fd, maplen - 1, seek_set) < 0) if(write(fd, "\0", 1) < 0) /*將檔案對映至程序的位址空間*/ pm = mmap(null, maplen, prot_read | prot_write, map_shared, fd, 0); if(pm == map_failed) /*關閉檔案描述符*/ close(fd); /*對檔案進行寫入操作*/ while(1)else i++; sleep(1); } munmap(pm, maplen); return 0; }
read.c
/*read.c*/
#include #include #include #include #include #include #include #define manlen 0x1000 struct stu ; void sys_err(char *str, int exitno) int main(int argc, char *ar**) fd = open(ar**[1], o_rdwr); if (fd < 0) pm = mmap(null, maplen, prot_read | prot_write, map_shared, fd, 0); if(pm == map_failed) /*關閉檔案*/ close(fd); /*刪除檔案*/ unlink(ar**[1]); /*在記憶體中讀資料*/ while(1) munmap(pm, maplen); return 0; }
yu@ubuntu:~/linux/211/tongxin$ ls
read.c write.c
yu@ubuntu:~/linux/211/tongxin$ gcc -o write write.c yu@ubuntu:~/linux/211/tongxin$ gcc -o read read.c yu@ubuntu:~/linux/211/tongxin$ ls read read.c write write.c
yu@ubuntu:~/linux/211/tongxin$ ./write myfile
//在向myfile檔案中寫資料
yu@ubuntu:~/linux/211/tongxin$ ls
read read.c write write.c myfile
yu@ubuntu:~/linux/211/tongxin$ ./read myfile 6 yu-6 m 7 yu-7 w ^c//讀取寫入的內容ctrl+c退出
ls，可發現myfile檔案已刪除
yu@ubuntu:~/linux/211/tongxin$ ls
read read.c write write.c
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