What is the recommended way for a C basic type to be passed-by-reference��to function wanting to use it for output.��

For example 'width' & 'height' here in this library unction...

�� int FPDF_GetPageSizeByIndex(FPDF_DOCUMENT document,

�� int page_index,

�� double* width,

�� double* height);

void mytestGetPageSizeByIndex(doc) {

�� double width, height;

�� FPDF_GetPageSizeByIndex(doc, 0, &width, &height);

�� printf("width=%f, height=%f\n", width, height);

}

gives...

�� width=200.000000, height=200.000000

In Pharo I'm trying...

�� FFIOpaqueObject subclass: #FPDF_DOCUMENT

�� FPDF_GetPageSizeByIndex__document: document
�� page_index: page_index
�� width: width
�� height: height

�� ^self ffiCall: #(int FPDF_GetPageSizeByIndex(

FPDF_DOCUMENT *document,

int page_index,

�� FFIFloat64 * width,��

FFIFloat64 * height))

testGetPageSizeByIndex

| document page_index width height result|

PDFium FPDF_InitLibrary.��

document := PDFium FPDF_LoadDocument__file_path:�� helloPdf�� password: ''.

width := 0.0.

height := 0.0.

page_index := 0. "Its zero based"

result := PDFium FPDF_GetPageSizeByIndex__document: document��

�� page_index: 0��

�� width: width��

�� height: height.

PDFium FPDF_CloseDocument__document: document.

PDFium FPDF_DestroyLibrary.

self assert: document isNull not. "Document opened okay, and btw this works for a different pageCount test"

self assert: result > 0.�� "Non-zero for success. 0 for error (document or page not found)"

self halt.

and at the halt the Inspector shows...

result = 1

width = 0.0

height = 0.0

cheers -ben