rc (LONG) - returns

This function returns one of the following:

TRUE

If the handle passed is recognized and no errors occurred.
FALSE
All other cases.
Possible Errors Detected: When an error is detected, the handling routine must call WinSetErrorInfo to post the condition. Error codes for conditions that the handling routine is expected to check include:

PMERR_INV_HDC
PMERR_NO_HANDLE

Refer to the "Error Explanations" section in the Presentation Manager Programming Reference for further explanation.