mkfifo()

//創(chuàng)建有名管道(FIFO special file)，創(chuàng)建完了就像普通文件一樣open(),再讀寫(xiě)，成功返回0,失敗返回-1設(shè)errno。VS$man 3 mkfifo#include #include int mkfifo(const char *pathname, mode_t mode);

pathname:the FIFO special file's name

mode?:the FIFO's permissions.

//創(chuàng)建FIFO管道文件int res=mkfifo(“./a.fifo”,0664);if(-1==res) perror("mkfifo"),exit(-1);res=open(“./a.fifo”,O_RDONLY);if(-1==res) perror(“open”),exit(-1);

pipe()

//創(chuàng)建無(wú)名管道,相當(dāng)于直接把open()返回的fd直接放到形參中,而不需額外的變量接收管道文件的描述符，用于父子進(jìn)程間通過(guò)管道進(jìn)行IPC通信,，成功返回0,失敗返回-1設(shè)errno#include int pipe(int pipefd[2]); //代碼自注釋?zhuān)硎舅枰膮?shù)是一個(gè)有兩個(gè)元素的數(shù)組，如果雖然作為形參，實(shí)質(zhì)上和int* pipefd沒(méi)有區(qū)別

pipefd?:return two fds referring to the ends of the pipe.

• pipefd[0] :read end,讀端
• pipefd[1] :write end,讀端.

fork()創(chuàng)建的child也會(huì)文件描述符總表也會(huì)復(fù)制一份So,對(duì)于child, 應(yīng)該先關(guān)閉讀端, 再寫(xiě),對(duì)于parent,應(yīng)該先關(guān)閉寫(xiě)端, 再讀

//使用pipe()實(shí)現(xiàn)父子進(jìn)程的通信#include#include#include#include#includeint main(){ //1. 創(chuàng)建無(wú)名管道 int pipefd[2]; int res=pipe(pipefd); if(-1==res) perror("pipe"),exit(-1); //2. 創(chuàng)建子進(jìn)程 pid_t pid=fork(); if(-1==pid) perror("fork"),exit(-1); //3. 子進(jìn)程開(kāi)始啟動(dòng),寫(xiě)入1~100; if(0==pid){ close(pipefd[0]); int i=0; for(i=1;i<=100;i++){ write(pipefd[1],&i,sizeof(int)); } close(pipefd[1]);//關(guān)閉寫(xiě)端 exit(0); } //4. 父進(jìn)程開(kāi)始啟動(dòng),讀取管道中的數(shù)據(jù) close(pipefd[1]); int i=0; for(i=1;i<=100;i++){ int x=0; read(pipefd[0],&x,sizeof(int)); printf("%d ",x); } printf("\n"); close(pipefd[0]); return 0;}