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The following functions are provided by GKS for handling errors detected
during calls to GKS:
- Error handling (GERHND) is called by GKS when an error is detected
during a call to a GKS function. The function can be replaced by an
application-supplied error-handling procedure, allowing customized
processing when errors are detected. The application-supplied
error-handling procedure can invoke any of the GKS inquiry functions;
it can also invoke either the Error logging (GERLOG) function or the
Emergency close GKS (GECLKS) function (or both) but it may not alter
the GKS state by invoking any other GKS functions. The Error handling
(GERHND) function merely calls the Error logging (GERLOG) function
described below.
- Error logging (GERLOG) can be called by the error-handling procedure
when an error has been detected by GKS. It causes a message
containing the GKS error number, the function in which it was
detected, and explanatory text to be written to the error file that is
specified when the Open GKS (GOPKS) function is called.
- Emergency close GKS (GECLKS) can be called by an application or by an
application-supplied error-handling procedure when errors are found.
Its function is to close GKS, but first to try to save as much of the
graphical information produced as possible.
Errors detected by the GKS inquiry functions do not cause the
error-handling procedure to be invoked, because the error number is
returned in an error indicator output parameter.
Error handling and application-supplied error-handling procedures are
discussed in more detail in "Using GDDM-GKS" in topic 4.0.
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GDDM-GKS V1R1 Programming Guide and Reference
Copyright IBM Corporation 1990, 2012