Passing ByRef or ByVal

[Just Me]

Public Declare Auto Function SendMessageRef Lib "user32.dll" Alias

"SendMessage" (ByVal hWnd As IntPtr, ByVal Msg As Integer, ByVal

wParam As Integer, ByRef lParam As PARAFORMAT2) As Integer



PARAFORMAT2 is a structure that SendMessage will return stuff in.

Is the ByRef correct or since only a pointer is being passed should it be

ByVal?



Suppose I was passing data rather then receiving it,

would that change the answer to the above?



Thanks in advance

 

[Herfried K. Wagner [MVP]]

Public Declare Auto Function SendMessageRef Lib "user32.dll" Alias

"SendMessage" (ByVal hWnd As IntPtr, ByVal Msg As Integer, ByVal

wParam As Integer, ByRef lParam As PARAFORMAT2) As Integer

PARAFORMAT2 is a structure that SendMessage will return stuff in.

Is the ByRef correct or since only a pointer is being passed should it be

Pass it 'ByRef'.

 

[Peter van der Goes]

Public Declare Auto Function SendMessageRef Lib "user32.dll" Alias

"SendMessage" (ByVal hWnd As IntPtr, ByVal Msg As Integer, ByVal

wParam As Integer, ByRef lParam As PARAFORMAT2) As Integer



PARAFORMAT2 is a structure that SendMessage will return stuff in.

Is the ByRef correct or since only a pointer is being passed should it be

ByVal?



Suppose I was passing data rather then receiving it,

would that change the answer to the above?



Thanks in advance

As you multiposted this same question to the C# group, please see my
response there.

 

[Just Me]

Thanks to both of you.
Needed the answer ASAP and got it ASAP