有名管道

建立了管道，两个进程就可以把它当作普通文件一样进行读写操作。

write.c

#include <sys/types.h> #include <sys/stat.h> #include <errno.h> #include <fcntl.h> #include <stdio.h> #include <stdlib.h> #include <limits.h> #define MYFIFO "/tmp/myfifo" /* 有名管道文件名*/ #define MAX_BUFFER_SIZE PIPE_BUF /*常量PIPE_BUF 定义在于limits.h中*/ int main(int argc, char * argv[]) /*参数为即将写入的字符串*/ { int fd; char buff[MAX_BUFFER_SIZE]; int nwrite; if(argc <= 1) { printf("Usage: ./fifo_write string\n"); exit(1); } sscanf(argv[1], "%s", buff); /* 以只写阻塞方式打开FIFO管道 */ fd = open(MYFIFO, O_WRONLY); if (fd == -1) { printf("Open fifo file error\n"); exit(1); } /*向管道中写入字符串*/ if ((nwrite = write(fd, buff, MAX_BUFFER_SIZE)) > 0) { printf("Write '%s' to FIFO\n", buff); } close(fd); exit(0); }

read.c

#include <sys/types.h> #include <sys/stat.h> #include <errno.h> #include <fcntl.h> #include <stdio.h> #include <stdlib.h> #include <limits.h> #include <string.h> #define MYFIFO "/tmp/myfifo" /* 有名管道文件名*/ #define MAX_BUFFER_SIZE PIPE_BUF /*常量PIPE_BUF 定义在于limits.h中*/ int main() { char buff[MAX_BUFFER_SIZE]; int fd; int nread; /* 判断有名管道是否已存在，若尚未创建，则以相应的权限创建*/ if (access(MYFIFO, F_OK) == -1) { if ((mkfifo(MYFIFO, 0666) < 0) && (errno != EEXIST)) { printf("Cannot create fifo file\n"); exit(1); } } /* 以只读阻塞方式打开有名管道 */ fd = open(MYFIFO, O_RDONLY); if (fd == -1) { printf("Open fifo file error\n"); exit(1); } while (1) { memset(buff, 0, sizeof(buff)); if ((nread = read(fd, buff, MAX_BUFFER_SIZE)) > 0) { printf("Read '%s' from FIFO\n", buff); } } close(fd); exit(0); }