get the cosole window size: why ioctl always return 0 width?

[karatelambda]

Hi, all,
I use ioctl to get the cosole window size (the SSH window). I use the following code:

-------------
struct winsize ws;
int returnValue = ioctl(pCommandStructure->terminal, TIOCGWINSZ, &ws);
int numberOfColumnsOfTerminalWindow = ws.ws_col;
-------------

When I debug on linux pc, it gives me the correct window width. But after I try it on router (this is my enventual place where my code shall run), ioctl always give me 0 width, that is, numberOfColumnsOfTerminalWindow == 0. but the returnValue is 0 which means that the function call succeeds.

Can anyonen tell me what is the problem and how to solve it?

Thanks a lot.

[Rubberman]

Using ioctl() for this is very problematic since they are VERY system dependent. It is not recommended usage. I'm not sure what the best system API call would be, but "stty size" will return the current tty console size in rows and columns.

[karatelambda]

Thanks. I tried "stty size", but no matter how I change the window size, it forever returns:
24 80