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getting return result from executing

Posted on 2004-09-13
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Last Modified: 2010-05-18
Hi, I need to execute another program from within my program and capture the result.  For example:

executing "bin/date +%H" will return "14" if it is 2 o clock
i need to capture the "14" into a variable int hr

i tried this:

int hr=execve("/bin/date","+%H",envp);

but all that does is run the date program, output the "14" and then it does not return a value.

I know that execve does not return a value unless it fails.

What command can I use to execute another command and get the output of it?

Sorry so long.
Thanks,
Josh
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Question by:jsm11482
2 Comments
 
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brettmjohnson earned 100 total points
ID: 12047785
You need to run popen("/bin/date +%H", "r") instead.
This runs the program, redirecting stdout to a pipe that
you can then read.

int hour = 0;
FILE * fp = popen("/bin/date +%H", "r");
if (fp) {
  fscanf(fp, "%d", &hour);
  pclose(fp);
}


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Author Comment

by:jsm11482
ID: 12047873
perfect, thanks!
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