is_windowed_mode (3) - Linux Manuals
is_windowed_mode: Tells if you are running in windowed mode. Allegro game programming library.
Command to display is_windowed_mode manual in Linux: $ man 3 is_windowed_mode
NAME
is_windowed_mode - Tells if you are running in windowed mode. Allegro game programming library.
SYNOPSIS
#include <allegro.h>
int is_windowed_mode(void);
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. */
}
RETURN VALUE
Returns true if the current graphics mode is a windowed mode, or zero if
it is a fullscreen mode. You should not call this function if you are not
in graphics mode.