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ryan.n

08-14-2004 09:15 PM

C function to execute a program and return the output of the program

Hello. I am making a program in C to display the song xmms is playing using xosd. The only problem I have is how to retrieve the current song. I figured the best way would be to execute

Code:

xmmsctrl title

What function can I use to execute a program in C and return the output? Please give the function name and header file.

Thank you for your time.

itsme86

08-14-2004 09:16 PM

'man popen'.

ryan.n

08-14-2004 09:48 PM

Code:

FILE *f=popen("xmmsctrl title","r");

char *ch;

puts(ch);

pclose(f);

this gives me a segmentation fault.

itsme86

08-14-2004 09:59 PM

And it should. You're referencing an unitialized pointer, the behavior of which is undefined. You're lucky your program didn't send an e-mail bomb to your employer about the use of company facilities.

Try this instead:

Code:

FILE *f = popen("xmmsctrl title", "r");

// Note: should really check if f == NULL here.

char buf[1024];

fgets(buf, sizeof(buf), f)

pclose(f);

printf("Now playing: %s", buf);

ryan.n

08-14-2004 10:11 PM

thanks

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