Description
The CPXgetlpcallbackfunc() is used to access the user-written callback routine which will be called after each iteration during the optimization of a linear program, and also periodically during the CPLEX presolve algorithm.Return Value
The routine returns a zero on success, and a nonzero if an error occurs.Synopsis
void CPXgetlpcallbackfunc (CPXENVptr env,
int (CPXPUBLIC **callback_p)
(CPXENVptr, void *, int, void *),
void **cbhandle_p);
CPXENVptr envThe pointer to the CPLEX environment as returned by one of the
CPXopenCPLEX routines.
int (CPXPUBLIC **callback_p) (CPXENVptr, void *, int, void *)The address of the pointer to the current user-written callback function. If no callback function has been set, the pointer will evaluate to NULL.
void **cbhandle_pThe address of a variable to hold the user's private pointer.
int callback (CPXENVptr env,
void *cbdata,
int wherefrom,
void *cbhandle);
CPXENVptr envThe pointer to the CPLEX environment that was passed into the associated optimization routine.
void *cbdataA pointer passed from the optimization routine to the user-written callback function that identifies the LP problem being optimized. The only purpose for the
cbdata pointer is to pass it to the CPXgetcallbackinfo() routine.
int wherefromAn integer value indicating from which optimization algorithm the user-written callback function was called. Possible values and their meaning appear in the table below.
void *cbhandlePointer to user private data, as passed to
CPXsetlpcallbackfunc() or CPXsetmipcallbackfunc().
status = CPXgetlpcallbackfunc (env, mycallback, NULL);