Correct passing NULL into DllCall string parameters Topic is solved

[vmech]

What is the mostly correct way to pass NULL into DllCall string parameters (e.g. for ShellExecuteW function): as a ('Str', ''), or as a ('Str', 0) ?

PS. The Autohotkey Reference explains passing NULL for numeric parameters, but does not cover this point for string parameters.

[jNizM]

For your example ShellExecuteW
LPCWSTR is a 32-bit pointer to a constant string of 16-bit Unicode characters, which MAY be null-terminated. So you could use "Ptr", 0

Maybe you find this useful: viewtopic.php?t=99817
And look at the explanation by lexikos: viewtopic.php?p=25611#p25611

[vmech]

Maybe you find this useful: viewtopic.php?t=99817

I use this tool all the time, TY

[jNizM]

e.g. with "Ptr"

Code: Select all

ShellExecute(handle, File, Operation, ...)
{
	DllCall("shell32\ShellExecuteW", "Ptr", handle									; HWND    hwnd
	                               , "Ptr", (Operation ? StrPtr(Operation) : 0)		; LPCWSTR lpOperation
	                               , "Str", File									; LPCWSTR lpFile
	                               , ...
}

or or or... all (many) roads lead to Rome

Use whatever is most understandable or clear to you