I think one major point is the unreadable mess, though. Is there a reason for this?
- Support for weird compilers
- Focus on performance, thus playing "weird" tricks with macros, lookup tables etc.
- especially in headers: protect against users doing crazy sh*t
- standards sometimes change or see extensions
- certainly more :)
First two items can be re-evaluated form time to time, but especially GNU often aims to run "anywhere"
The third item comes from the fact that users can create macros for many things and only some names (leading _ and capital letter or __) are reserved for standards or C++ allowing to overload the comma operator, which can have weird effects. Thus to be conformant to the standards some ugliness is required.
The fourth point combined with different compatibility requirements requires tricks to switch between different implementations based on compiler flags/macros (for instance `#define _GNU_SOURCE` or `#define _POSIX_C_SOURCE=...`)
I understand both sides of the argument here - on one hand you have fast and unreadable code and on the other hand slower and more readable code. The problem here is 1. the leaky abstraction of characters and code points and 2. loss of type safety due to C's weak typing rules, which is a bit lost in the "hurr durr messy code."
Do you have a source for this claim?
I find it hard to believe that Microsoft would drop support for ANSI applications.