The most recent Optimizer
error number that occurred. This is
useful to determine the precise error or warning that has occurred, after an Optimizer function has
signalled an error by returning a non-zero value. The return value itself is
not the
error number. Refer to the section
Optimizer Error and Warning Messages for a list of
possible error numbers, the errors and warnings that they indicate, and advice on what they mean and
how to resolve them. A short error message may be obtained using
XPRSgetlasterror, and all messages may be intercepted using the user output
callback function; see
XPRSsetcbmessage.