[lmm]

> you can of course use non-C languages to call the Win32 API. Or even directly using assembly code.

Is that a supported/official API though? On Linux you "can" put your arguments in registers and trigger the system call interrupt directly, and I think Go programs even do this, but it's not the official interface and they reserve the right to break your program in future updates, at least in theory.

[mjg59]

This is incorrect. The syscall ABI is the supported stable ABI for Linux, not the libc API - there's no single supported C library for Linux, and libc often lags behind the kernel in terms of providing syscall wrappers, so punting it to that level wouldn't work. This is in contrast to the BSDs that have libc tightly coupled to the kernel.

Of course, the Linux solution results in some weirdness, especially because specs like POSIX cover the C API, not the syscall ABI. setuid() at the libc layer is specced as changing the UID for all threads in a process. The Linux setuid() syscall only changes the current thread[1], and it's up to the C library to do some absolute magic to then propagate that to all other threads. Which made things difficult for things not using the C library, like Go (https://github.com/golang/go/issues/1435). But that's still not an argument that the supported interface is the C library - the kernel advertises the interface it exposes via the syscall ABI, and will retain that functionality, and if you want POSIX compatibility then you get it from somewhere else.

[1] In Linux, a thread is just a very slightly special case of a process

[teraflop]

Sure. C has never been the only language supported on Windows.

For instance, Delphi had a period of popularity for Windows application development, and AFAIK it has always used its own runtime library which is completely independent of the C runtime.

Go does not trigger low-level system call interrupts on Windows. (It does that on Linux, but Windows syscall numbers are not stable even across minor Windows updates, so if Go did that, its Windows binaries would be incredibly fragile.)

On Windows NT, Go uses the userspace wrappers provided in Windows system libraries such as NTDLL.DLL and KERNEL32.DLL. But those too are entirely separate from the C runtime.

[JdeBP]

Don't forget the days when multiple C/C++ implementations from multiple vendors all came with their own runtime library DLLs, too.

[Pannoniae]

Calling win32 from other languages is supported, calling it from assembly is supported (as long as you use the calling convention properly, obviously), using ntdll to bypass the win32 API is not supported.

Basically on Linux the syscalls are the equivalent of Win32 except much narrower in scope.

[account42]

> using ntdll to bypass the win32 API is not supported

But it is sometimes required to do things properly.

[wvenable]

> Is that a supported/official API though?

The Win32 API doesn't even use the "C" calling convention. C is just another language to Windows and the standard C library is a cross-platform library for C. You could also write C code on classic Mac OS and it had it's own API as well but more styled for Pascal.

The OS and C being closely related is not universal across all operating systems, it's just a Unix thing.