The usual workarounds are a stateful API (e.g. Cairo, OpenGL, or Windows GDI), passing a structure explicitly (oodles of examples in Win32, e.g. RegisterClass or GetOpenFileName), or a twiddling an object that’s actually just a structure dressed up in accessor methods (IOpenFileDialog).
There could be reasons to use one of those still (e.g. extensibility while keeping a compatible ABI, as in setsockopt, pthread_attr_*, or arguably posix_spawnattr_*). But sometimes you really do need a finite, well-known but just plain large number of parameters that mostly have reasonable defaults. Old-style 2D APIs to draw and/or stroke a shape (or even just a rectangle) are the classic example. Plotting libraries (in all languages) are also prone to this. It does seem like these situations are mostly endemic to specific application areas—graphics of all kinds first of all—but that doesn’t make them not exist.
If you don’t want to use function-like macros for anything ever even if this particular one works, that’s a valid position. But it does work, it does solve a real problem, and it is less awkward at the use site than the alternatives.
With large numbers of parameters, it's almost always more readable to use a config struct. Especially since often, you want to collect configuration from multiple sources, and incrementally initializing a struct that way is helpful.
There could be reasons to use one of those still (e.g. extensibility while keeping a compatible ABI, as in setsockopt, pthread_attr_*, or arguably posix_spawnattr_*). But sometimes you really do need a finite, well-known but just plain large number of parameters that mostly have reasonable defaults. Old-style 2D APIs to draw and/or stroke a shape (or even just a rectangle) are the classic example. Plotting libraries (in all languages) are also prone to this. It does seem like these situations are mostly endemic to specific application areas—graphics of all kinds first of all—but that doesn’t make them not exist.
If you don’t want to use function-like macros for anything ever even if this particular one works, that’s a valid position. But it does work, it does solve a real problem, and it is less awkward at the use site than the alternatives.