plxormod: Enter or leave xor mode

plxormod (mode, status);

Enter (when mode is true) or leave (when mode is false) xor mode for those drivers (e.g., the xwin driver) that support it. Enables erasing plots by drawing twice the same line, symbol, etc. If driver is not capable of xor operation it returns a status of false.

mode (PLBOOL, input)

mode is true means enter xor mode and mode is false means leave xor mode.

status (PLBOOL *, output)

Pointer to status. Returned modestatus of true (false) means driver is capable (incapable) of xor mode.

Redacted form: plxormod(mode, status)

This function is used in examples 1,20.