How do I get the effect of C#’s async void in a C++ coroutine? Part 3: Simplifying the boilerplate

Raymond Chen January 18, 2019 Jan 18, 2019 01/18/19

Factoring it out.

How do I get the effect of C#’s async void in a C++ coroutine? Part 2: Keeping track of the lifetimes

Raymond Chen January 17, 2019 Jan 17, 2019 01/17/19

There are two types of lambdas you have to write, so why not write two lambdas?

How do I get the effect of C#’s async void in a C++ coroutine? Part 1: Why does the obvious solution crash?

Raymond Chen January 16, 2019 Jan 16, 2019 01/16/19

The co_await C++ language keyword makes it a lot easier to write coroutines. The compiler does the grunt work of transforming your function into a state machine, similar in spirit to the coroutine transformations performed by C# and JavaScript. C# and JavaScript have an additional feature that C++ doesn't: They let you take a coroutine and ...

Don’t pass lambdas (or other multi-line entities) as parameters to macros

Raymond Chen January 15, 2019 Jan 15, 2019 01/15/19

Consider this macro: This seems not entirely unreasonable, but bad things happen if you pass a multi-line entity as the macro parameter. You will never to be able to debug this lambda, because the preprocessor slurps up the entire macro parameter list, and then spits the text back out when the macro is expanded. But when it spits the text ...

Why do we even need to define a red zone? Can’t I just use my stack for anything?

Raymond Chen January 11, 2019 Jan 11, 2019 01/11/19

On Windows, the stack grows downward from high addresses to low. This is sometimes architecturally defined, and sometimes it is merely convention. The value pointed-to by the stack pointer register is the value at the top of the stack, and values deeper on the stack reside at higher addresses. But what's up with the data at addresses less than...

Why am I getting mojibake when I try to create a window?

Raymond Chen January 10, 2019 Jan 10, 2019 01/10/19

A customer was compiling their program as Unicode, but since their data was almost all in ASCII, they were using the ANSI versions of the APIs. They registered their class with the Register­ClassA function and created it with the Create­Window­ExA function. But the window title came out as Chinese mojibake. But not all strings ...

STATUS_STACK_BUFFER_OVERRUN doesn’t mean that there was a stack buffer overrun

Raymond Chen January 8, 2019 Jan 8, 2019 01/8/19

A category of dubious security vulnerability is people who recently discovered the STATUS_STACK_BUFFER_OVERRUN status code. The confusion is made even worse by the fact that the human-readable description is The system detected an overrun of a stack-based buffer in this application. This overrun could potentially allow a malicious user to ...

The GetRegionData function fails if the buffer is allocated on the stack. Is it allergic to stack memory or something?

Raymond Chen January 7, 2019 Jan 7, 2019 01/7/19

If you pass a NULL buffer to the Get­Region­Data function, the return value tells you the required size of the buffer in bytes. You can then allocate the necessary memory and call Get­Region­Data a second time. This version of the code works just fine. We call the Get­Region­Data function to obtain the number of bytes ...