ILOG CPLEX 11.0 User's Manual

shows you the default, the maximum, and the minimum values of a given parameter of typedouble, and the routine CPXinfostrparam shows you the default value of a given stringparameter. Those three Callable Library routines observe the same conventions: theyreturn 0 (zero) from a successful call and a nonzero value in case of error.The routines CPXinfointparam and CPXinfodblparam expect five arguments:◆◆◆◆◆a pointer to the environment; that is, a pointer of type CPXENVptr returned byCPXopenCPLEX;an indication of the parameter to check; this argument may be a symbolic constant, suchas CPX_PARAM_CLOCKTYPE, or a reference number, such as 1006; the symbolicconstants and reference numbers of all ILOG CPLEX parameters are documented in thereference manual ILOG CPLEX Parameters and they are defined in the include filecplex.h.a pointer to a variable to hold the default value of the parameter;a pointer to a variable to hold the minimum value of the parameter;a pointer to a variable to hold the maximum value of the parameter.The routine CPXinfostrparam differs slightly in that it does not expect pointers tovariables to hold the minimum and maximum values as those concepts do not apply to astring parameter.To access the current value of a parameter that interests you from the Callable Library, usethe routine CPXgetintparam for parameters of type int, CPXgetdblparam forparameters of type double, and CPXgetstrparam for string parameters. These routinesalso expect arguments to indicate the environment, the parameter you want to check, and apointer to a variable to hold that current value.No doubt you have noticed in other chapters of this manual that you can set parameters fromthe Callable Library. There are, of course, routines in the Callable Library to set suchparameters: one sets parameters of type int; another sets parameters of type double;another sets string parameters.◆◆CPXsetintparam accepts arguments to indicate:●●●the environment; that is, a pointer of type CPXENVptr returned by CPXopenCPLEX;the parameter to set; this routine sets parameters of type int;the value you want the parameter to assume.CPXsetdblparam accepts arguments to indicate:●●●the environment; that is, a pointer of type CPXENVptr returned by CPXopenCPLEX;the parameter to set; this routine sets parameters of type double;the value you want the parameter to assume.124 ILOG CPLEX 11.0 — USER’ S MANUAL