void gpcTextMode(on_off) BAUX?.C Level 1
int on_off = 1 Switch to text mode or display text window. 
= 0 Switch to graphics mode or hide text window (default).
GPCTextMode() is a macro that behaves somewhat differently in DOS and windowing environments. 
In non-windowed environments gpcTextMode() allows you to return to text mode after GraphiC has been initiated by a call to bgnplot(). GraphiC must be returned to graphics mode before any graphics are produced, and before the call to endplot(). It is quite important that you return to graphics mode when graphics are produced or your program may hang up. Also, the graphics screen will not be restored, so it is best to arrange for your text-mode output to occur before the call to startplot() or after the call to endplot() in a multi-plot program. Text should be output using GPC_PUTS() or GPC_SPUTS() for compatibility across platforms. 
In windowed environments, you can have GraphiC display a second window which will scroll all text that is output by GPC_SPUTS(). The window can accept text at any time, and remains active (although hidden) if on_off = 0. GPC_PUTS() will display text in a pop-up message box that must be dismissed by the user.