rtGrdpInstanceData.h File Reference

Customizes the typedef GRDP_RTITEM declaration. More...

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Macros
#define	GRDP_RUNTIME_INSTDATADECL   MY_GRDP_DATA* data;
	Implementation defined runtime instance data macro. More...

Detailed Description

Customizes the typedef GRDP_RTITEM declaration.

During import, it is often necessary to keep track of runtime, shared state information. To simplify the addition of this kind of data to a plugin without having to resort to global variables, or adding arguments to functions, a pointer to plugin defined data type is part of GRDP_RTITEM.

To add custom, per-instance data to the GRDP_RTITEM typedef, your plugin should define the struct MY_GRDP_DATA. For example, in runtimeReadGrid.cxx (for local use) or in a project header file (for shared use) you could define:

struct MY_GRDP_DATA {
    int     count;
    int     offset;
    float   scale;
    char *  name;
};

A pointer to this struct is accessed as pRti->data using the pRti parameter of runtimeReadGrid(GRDP_RTITEM *pRti). By default, pRti->data is set to null.

To use this pointer, a plugin needs to declare and initialize an instance of this struct and assign its address to this pointer. Once set, your plugin can access the MY_GRDP_DATA data members anywhere it has access to the pRti pointer.

An example is shown in the code below.

PWP_BOOL runtimeReadGrid(GRDP_RTITEM *pRti)
{
    MY_GRDP_DATA localData;
    pRti->data = &localData;
 
    // Assuming the definition given above, these are now valid
    pRti->data.count;
    pRti->data.offset;
    pRti->data.scale;
    pRti->data.name;
 
    // someFunc also can access this data!
    someFunc(pRti);
}

Definition in file rtGrdpInstanceData.h.

Macro Definition Documentation

GRDP_RUNTIME_INSTDATADECL

#define GRDP_RUNTIME_INSTDATADECL   MY_GRDP_DATA* data;

Implementation defined runtime instance data macro.

By default, this macro resolves to MY_GRDP_DATA* data;.

See rtGrdpInstanceData.h for more information.

Definition at line 22 of file rtGrdpInstanceData.h.