c++ system return

prongs_386 · 07-11-2007, 12:50 AM

Hi,
just wondering whether it is possible to get the feedback from console from something called within the system() command.
eg.
system("service dhcpd status");
would print into console whether the dhcpd service is running, however this information isnt returned to the program as far as i'm aware.

Is it possible to retrieve this output?

Thanks

wjevans_7d1@yahoo.co · 07-11-2007, 07:53 AM

There are several ways, depending on your taste.

First, if you want the output to go to the console and to the program, you can do this:

Code:

system("service dhcpd status | tee tempfile.txt");

and then read file tempfile.txt in your program.

Another way would be to do I/O redirection by hand, using fork(), exec(), and other calls. Effectively, your program would do much of what bash or other shells do. To get started, go here:

http://www.gnu.org/software/libc/man...scriptors.html
http://www.gnu.org/software/libc/man...Launching-Jobs

These pages are intended for C users, but C++ users will find them interesting also.

Hope this helps.

ta0kira · 07-11-2007, 08:10 AM

'system' inherits standard input/output/error from the calling process. Try 'popen' instead of 'system'. If not, you will need to 'pipe', 'fork', 'dup2', then 'system'. There is more to it than that, so I think 'popen' is the way to go.
ta0kira