I'm working in a function with bp based frame and a typical instruction might be: mov ecx, [bp+arg_4].

The IDC function GetOpnd(ea,1) returns the string: [bp+arg_4], and GetFlags will tell me that [bp+arg_4] is a stack variable.

But which function will get me the Member Offset within the frame of arg_4 directly from the operand [bp+arg_4].

I can parse the [bp+arg_4] string and use GetMemberOffset(id,arg_4), but sometimes I have re-named the arguments or the operand looks like [bp+38h+arg_4], etc. There must be a built-in function I'm missing.

Thanks in advance.