A lambda expression be compiled on 64 platform but causes compile error on 32

Asked Sep 18 '15 at 07:49

Active Sep 18 '15 at 08:49

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I have a simple lambda expression as:

EnumWindows([] (HWND hWnd, LPARAM lparam) -> BOOL {return FALSE;}, 0);

It successfuly is compiled on 64 bit platform but causes following error on 32 bit:

[CLANG Error] Unit3.cpp(15): no matching function for call to 'EnumWindows'
  winuser.h(9766): candidate function not viable: no known conversion from '<lambda at Unit3.cpp:15:14>' to 'WNDENUMPROC' (aka 'BOOL (*)(HWND, LPARAM) __attribute__((stdcall))') for 1st argument

Anybody has an idea?

edited Sep 18 '15 at 08:49

asked Sep 18 '15 at 07:49

mh taqia

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This looks relevent http://stackoverflow.com/questions/17714175/how-to-use-stdcall-to-qualify-c-lambda – jcoder Sep 18 '15 at 08:01
I have seen it, was not useful. It seems it works on 64 bit compile. – mh taqia Sep 18 '15 at 08:23
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@jcoder: that other question is for Visual Studio, not for C++Builder. – Remy Lebeau Sep 18 '15 at 08:24
You need to qualify the lambda as `__stdcall`. 64 bit has only 1 calling convention so this is never a problem. You need to check if your compiler has a dedicated syntax to do that. – sbabbi Sep 18 '15 at 10:07
@sbabbi: how to qualify the lambda as __stdcall? – mh taqia Sep 18 '15 at 10:42
@mhtaqia http://stackoverflow.com/questions/14169295/how-to-specify-vc11-lambda-calling-convention – sbabbi Sep 18 '15 at 11:43
@sbabbi: Fails. Compile error. – mh taqia Sep 18 '15 at 16:42
@mhtaqia Then I guess you are out of luck. – sbabbi Sep 18 '15 at 16:44

A lambda expression be compiled on 64 platform but causes compile error on 32

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