PS:
1. The sample is type of IPC program, and the command need to go with pipe line( "|" )
2. The sample is referenced from http://www.computing.net/answers/programming/unix-command-in-c/19012.html nalls's reply
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complier: gcc command.c -o command
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source code:
#include
#include
#include
#define MAX_LINES 256
#define MAX_CHARS MAX_LINES
#define MAX_TXT MAX_LINES
/*
* This function executes a piped command passed as
* a pointer-to-string, exe_str.
* buffer is the array where each line is stored
* lineptr is an array-of-pointers where each element of the
* array points to the beginning of each line stored in buffer.
*
* returns the number of lines read into buffer, cnt.
*
* URL: http://www.computing.net/answers/programming/unix-command-in-c/19012.html
*/
/*
* Fatal Error
*/
int fatal(x)
char *x;
{
perror(x);
exit(1);
}
int run_popen(lineptr, buffer, exe_str)
char *lineptr[]; /*array-of-pointers to addresses */
char buffer[]; /*buffer to save strings */
char *exe_str; /*pipe command */
{
int i, cnt=0;
FILE *ptr, *popen();
char *bufstart, *bufend, line[MAX_TXT], *fgets();
bufstart = buffer; /*mark start of available space*/
bufend = buffer + MAX_CHARS; /*mark end of available space*/
if((ptr = popen(exe_str, "r")) == NULL)
fatal("Couldn't open pipe");
for(i=0; i
{
if(fgets(line, MAX_TXT, ptr) == NULL)
break;
line[strlen(line)-1] = '\0'; /* no new-lines*/
if((bufstart + strlen(line) + 1) >= bufend)
fatal("Line too long");
lineptr[i]=bufstart; /*save the address of the line*/
strcpy(bufstart,line); /*save the line into buffer*/
bufstart += strlen(line)+1; /*update starting pointer*/
cnt++;
}
fclose(ptr);
return cnt;
}
int main()
{
char *slines[MAX_LINES];
char sbuf[MAX_CHARS];
char *com_str="ifconfig | ifconfig eth0 |grep inet";
int count,i;
count=run_popen(slines, sbuf, com_str);
fprintf(stderr,"count is %d\n", count);
if(count == 0)
exit(1);
for(i=0; i
printf("%s\n", slines[i]);
return 0;
}
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