thinhare
25th September 2007 08:10 UTC

Confusion on GetKeyboardLayoutList Function
I am confused with the usage of this code in red:

System::Call 'user32::GetKeyboardLayoutList(i ${NSIS_MAX_STRLEN},i R0)i.r4'

should it not be with a dot: i .R0 ?

in MSDN it says:

UINT GetKeyboardLayoutList(int nBuff, HKL *lpList);

nBuff
[in] Specifies the maximum number of handles that the buffer can hold.
lpList
[out] Pointer to the buffer that receives the array of input locale identifiers.

does OUT not mean DESTINATION?

CancerFace
25th September 2007 08:42 UTC

Yes, OUT means destination. It depends however on the type of output.

In your example the output is a memory buffer and if it has been pre-alocated then there is no reason to use a dot.

Also, it is a pointer which implies the use of a *
However, if it is a pre-allocated buffer, then the variable that points to it is already a pointer, so no need for the *

Check the entire call:

System::Alloc ${NSIS_MAX_STRLEN}
  Pop $R0
System::Call 'user32::GetKeyboardLayoutList(i ${NSIS_MAX_STRLEN}, i R0)i.r0'

The first part allocates a portion of memory equal to ${NSIS_MAX_STRLEN} and then the buffer location is popped into $R0. So when the second call occurs, $R0 is already a pointer to a buffer, so it is referenced as iR0 rather than *iR0 or *i.R0.

Hope this helps,
CF