>Can anyone provide some insight in converting structs and pointers to VFP strings ? I am trying to use a call to the HTML help object to display a popup with the following syntax:
>
>HTMLHelp(0,"",HH_DISPLAY_TEXT_POPUP, @lpHH_POPUP)
>
>I need to pass a pointer HH_POPUP structure to this function as the last parameter, which is what I am stuck on. The structure of the popup is as follows:
>
>typedef struct HH_POPUP
>{
>int cbStruct;
>HINSTANCE hinst;
>UINT idString;
>LPCTSTR pszText;
>POINT pt;
>COLORREF clrForeground;
>COLORREF clrBackground;
>RECT rcMargins;
>LPCTSTR pszFont;
>} HH_POPUP;
>
>I know that pt is a pointer to a POINT structure, which is defined as two LONGs that hold the X and Y co-ordinates of the cursor. The RECT structure is 4 LONGS that store the co-ordinates of the window to create. The pszText and pszFont are pointers to strings, if I am following this correctly.
>
>How (or CAN) I map this structure to a VFP string ? I have tried some routines I found here and in some books I have but have had no luck. Also, the cbStruct INTEGER needs to contain the size of the structure, how would I figure this out ? Is it impossible to pass this ???
Not impossible, but a bit difficult because of the pointers. You'll need to allocate space outside of VFP-controlled memory variables to hold the things pointed at because (1) there's no convenient way to grab the address of a VFP string to embed a pointer in a structure, and (2) VFP's string memory space can be rearranged on the fly, so if you did manage to get a pointer, there's no way to prevent VFP from moving it around 9short of the C API, in which case you can write a wrapper .DLL). The easiest solution, short of writing a wrapper .DLL in C or C++ to handle the task of creating and managing the structure for you, would be to take a look at Paul Tatavu's POINTERS class (it's available for download here on UT).
