plz help me to understand function call

[codedemen]

Ive got a func(Hex rays)

sub(void *this, int a2, char a3)

and here is a call to it:

 sub(*(_DWORD *)v5, 1);

The question is:
would *this be *(_DWORD *)v5, a2 = 1 and a3 null OR a2 is *(_DWORD *)v5 and a3 is 1, then how to find what is this in that case?

Thak you for your help!

[danwins]

*this is the this pointer passed on the ECX register as part of the __thiscall calling convention.

see https://msdn.microsoft.com/en-us/library/ek8tkfbw.aspx

[Jadd]

Hex-rays updates function definitions as they are decompiled. It probably won't recognise "sub" is a __thiscall until it has also been decompiled, so it doesn't realise it needs to show ecx as a parameter, too.

Decompile "sub", then go back and decompile the caller function, and you'll probably notice it will then pass 3 parameters, like it should.

[codedemen]

Thank you! Just have been using too old ida version =)