10-3.c

《Linux应用开发技术详解》附书光盘中的例程。

#include <stdio.h>
#include <string.h>

int main(void)
{
        char buf[256];
        FILE * fp = popen("./calculator", "w");
        if ( fp == NULL) {
                printf("Fail to poen ./calculator...\n");
                exit(－1);
        }
        while (1) {
                printf("Enter a expression: ");
                fgets(buf, 256, stdin);
                if  (strncmp("quit", buf, 4) == 0) {
                        fprintf(fp, "\n");
                        fflush(fp);
                        pclose(fp);
                        exit(0);
                }
                fprintf(fp, "%s", buf);
                fflush(fp);
                sleep(1);
        }

}