The KW_RESULT Structure

Each system routine that processes keywords is required to define a structure variable into which IDL_KWProcessByOffset() will store all the results of keyword processing. This variable must follow the following rules:

The name of the structure type must be defined as KW_RESULT. This requirement exists so that the IDL_KW_OFFSETOF() macro can properly do its work.

The first field within any KW_RESULT structure must be defined using the IDL_KW_RESULT_FIRST_FIELD macro. The contents of this first field are private, and should not be examined. It contains the information required by IDL to properly track its resource use.

The name of the KW_RESULT variable must be kw. This requirement exists so that the IDL_KW_FREE macro can properly do its work.

Hence, all system routines that process keywords will contain statements similar to the following:

typedef struct { 
    IDL_KW_RESULT_FIRST_FIELD;	/* Must be first entry in struct */ 
    ...                       /* Additional user specified fields */ 
  } KW_RESULT; 
 
  KW_RESULT kw;

All fields within the KW_RESULT structure after the required first field can have arbitrary user selected names. The types of these fields are dictated by the IDL_KW_PAR and IDL_KW_ARR_DESC_R structures that refer to them.