is_windowed_mode (3) - Linux Manuals
is_windowed_mode: Tells if you are running in windowed mode. Allegro game programming library.
NAME
is_windowed_mode - Tells if you are running in windowed mode. Allegro game programming library.SYNOPSIS
#include <allegro.h>
DESCRIPTION
This function can be used to detect whether or not set_gfx_mode() selected a windowed mode. Example:
if (set_gfx_mode(GFX_AUTODETECT, 640, 480, 0, 0) != 0) abort_on_error("Couldn't set graphic mode!"); if (is_windowed_mode()) { /* Windowed mode stuff. */ } else { /* Fullscreen mode stuff. */ }