popen()函数详解

popen()函数

 1 /*============================================

 2   > Copyright (C) 2014 All rights reserved.

 3   > FileName：popen.c

 4   > author：donald

 5   > date：2014/08/22/ 12:20:53

 6   > details：

 7 ==============================================*/

 8 #include <unistd.h>

 9 #include <stdio.h>

10 #include <stdlib.h>

11 #include <string.h>

12 #define N 512

13 int main(int argc, const char *argv[])

14 {

15     FILE *fp;

16     char cmd[N],buf[N];

17     memset(cmd,0,N);

18     memset(buf,0,N);

19 #if 0

20     fgets(cmd,N,stdin);

21     fp = popen(cmd,"r");

22     while(fgets(buf,N,fp) != NULL)

23         printf("%s",buf);

24 #endif

25 #if 1

26     fgets(cmd,N,stdin);

27     fp = popen(cmd,"w");

28     //这里把用户输入写进了cmd，

29     if(fp == NULL)

30         printf("error\n");

31     fgets(buf,N,fp);

32     printf("123%s\n",buf);//测试时使用

33 #endif

34     pclose(fp);

35     return 0;

36 }

open_mode为“r”

open_mode为“w”

 1 /*============================================

 2 > Copyright (C) 2014 All rights reserved.

 3 > FileName：my_ponen.c

 4 > author：donald

 5 > details：

 6 ==============================================*/

 7 #include <unistd.h>

 8 #include <stdio.h>

 9 #include <stdlib.h>

10 #include <string.h>

11 int main(int argc, const char *argv[])

12 {

13 int left,right,sum;

14 FILE* fp ;

15 char cmd[1024] = "";

16 while(1){

17 scanf("%d%d",&left,&right);

18 sprintf(cmd,"%s %d %d",argv[1],left,right);

19 fp = popen(cmd,"r");

20 fscanf(fp,"%d",&sum);

21 printf("result is : %d\n",sum);

22 

23 pclose(fp);

24 }

25 return 0;

26 }

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目标函数

 1 /*============================================

 2   > Copyright (C) 2014 All rights reserved.

 3   > FileName：mystring.c

 4   > author：donald

 5   > details：

 6 ==============================================*/

 7 #include <stdio.h>

 8 #include <stdlib.h>

 9 #include <string.h>

10 #define N 1024

11 int main(int argc, const char *argv[])

12 {

13     int index;

14     char buf[N];

15     memset(buf,0,N);

16     for(index = argc - 1;index > 0;index --){

17         strcat(buf,argv[index]);

18         strcat(buf," ");

19     }

20     printf("%s\n",buf);

21     return 0;

22 }

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