SysCall

名前なしパイプ(2)と同じようなことをここではします. また整数の加算です.

クライアントサイドプログラム

/* client.c */
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<unistd.h>
#include<sys/stat.h>
#include<sys/types.h>
#include<fcntl.h>

#define FIFO0 "./FIFO0" //Read
#define FIFO1 "./FIFO1" //Write

void error_message(const char *name);
void unlink_pipe(void);

int main(int argc, char **argv)
{
    int fd0, fd1;
    char buff[32], result[32];

    if((fd0 = open(FIFO0, O_RDONLY)) == EOF || (fd1 = open(FIFO1, O_WRONLY)) == EOF)
        error_message("open");

    printf("NumA:");
    fgets(buff, 32, stdin);
    if(write(fd1, buff, strlen(buff) + 1) == EOF)
        error_message("write");

    printf("NumB:");
    fgets(buff, 32, stdin);
    if(write(fd1, buff, strlen(buff) + 1) == EOF)
        error_message("write");

    if(read(fd0, result, 32) == EOF)
        error_message("read");

    printf("Answer = %s\n", result);

    unlink_pipe();

    return 0;
}

void error_message(const char *name) {
    perror(name);
    exit(EXIT_FAILURE);
}

void unlink_pipe(void) {
    if(unlink(FIFO0) == EOF)
        error_message("unlink");
    if(unlink(FIFO1) == EOF)
        error_message("unlink");
}

/* server.c */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>

#define FIFO0 "./FIFO0" //Write
#define FIFO1 "./FIFO1" //Read

void error_message(const char *name);

int main(int argc, char **argv)
{
    int fd0, fd1;
    int na, nb, nc;
    char buff[32], result[32];

    if(access(FIFO0, 0777) == EOF)
        mkfifo(FIFO0, 0777);
    if(access(FIFO1, 0777) == EOF)
        mkfifo(FIFO1, 0777);

    if((fd0 = open(FIFO0, O_WRONLY)) == EOF)
        error_message("open");
    if((fd1 = open(FIFO1, O_RDONLY)) == EOF)
        error_message("open");

    if(read(fd1, buff, 32) == EOF)
        error_message("read");
    na = atoi(buff);

    printf("Get Number A = %d\n", na);

    if(read(fd1, buff, 32) == EOF)
        error_message("read");
    nb = atoi(buff);

    printf("Get Number B = %d\n", nb);

    nc = na + nb;

    printf("Returned Answer to Client...\n");

    sprintf(result, "%d", nc);

    if(write(fd0, result, strlen(result) + 1) == EOF)
        error_message("write");

    return 0;
}

void error_message(const char *name) {
    perror(name);
    exit(EXIT_FAILURE);
}