Glide provides a family of error management functions to assist a developer with application debugging.
This family of routines consists of :

Glide related error management (errors generated by Glide) and

application level error management (errors generated by an application).

The debug build of Glide performs extensive parameter validation and resource checking. When an error condition is detected, a user supplied call-back function may be executed. This call-back function is installed by calling grErrorSetCallback(). If no call back function is specified, a default error function that prints an error message to stderr is used.

The call-back function accepts a string describing the error and a flag indicating if the error is fatal or recoverable. grErrorSetCallback() is relevant only when using the debugging version of Glide; the release build of Glide removes all internal parameter validation and error checking so the call-back function will never be called.