What do these parameters mean?

[polatchekm]

I'm trying to use createfile() in a user function. The documentaton has the following snippet:

#define EXAMPLE_DIR "C:\\"
#define EXAMPLE_FILE "ISExampl.txt"
// Include Ifx.h for built-in InstallScript function prototypes.
#include "Ifx.h"

export prototype ExFn_CreateFile(HWND);

function ExFn_CreateFile(hMSI)
STRING szTitle, szMsg;
NUMBER nvFileHandle;
begin
// Set the file mode to append.
OpenFileMode (FILE_MODE_APPEND);

What do the parameters HWND and hMSI represent?

This will be my first user function in IS.

Thanks,
Mel Polatchek

[phill_mn]

This example code is for an InstallScript MSI Custom Action. Is that what you are trying to create?

All MSI Custom Actions have an entry point function which has a single argument typically named "hMSI" which is a handle to the MSI install instance that the Custom Action is running in. In InstallScript code a Windows handle is declared as type HWND.

[polatchekm]

This is a modification to an existing Installscript project. The documentation does not say MSI only, I am assuming I can make it work within Installscript as a User Def Function. Thanks for the tip about the handle.

[phill_mn]

The example code where that snippet came from does indicate that it should be used in a MSI custom action.
"Note To call this function in a Basic MSI setup, you must first create a custom action for the entry-point function, execute the custom action in a sequence or as the result of a dialog's control event, and then build the release."

http://kb.flexerasoftware.com/doc/Helpnet/installshield15langref/LangrefCreateFile_Example.htm

I would agree that the above note does not make it clear that the code will not work, as is, in anything other than a MSI custom action, but that is implied.

If your function is not being called in the context of a custom action, then change the function prototype to reflect that there would not be a MSI handle.

#define EXAMPLE_DIR "C:\\"
#define EXAMPLE_FILE "ISExampl.txt"
// Include Ifx.h for built-in InstallScript function prototypes.
#include "Ifx.h"

export prototype My_CreateFile();

function My_CreateFile()
STRING szTitle, szMsg;
NUMBER nvFileHandle;
begin
// Set the file mode to append.
OpenFileMode (FILE_MODE_APPEND);

.....