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Comment by cesarb | Hacker News Reader

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The Linux kernel makes heavy use of GCC extensions, like statement expressions (https://gcc.gnu.org/onlinedocs/gcc-8.2.0/gcc/Statement-Exprs...), __builtin_constant_p (https://gcc.gnu.org/onlinedocs/gcc-8.2.0/gcc/Other-Builtins....), and GCC-style inline assembly. Since this means the kernel can only be compiled by gcc (or compilers which try to mimic gcc like clang, which pretends to be gcc 4.2.1), it makes sense to treat GCC (actually "the C89 standard plus GCC extensions") as the standard.

> it makes sense to treat GCC (actually "the C89 standard plus GCC extensions") as the standard.

While that might have been the case, this announcement says that one of the many reasons to stop using VLAs is to allow the kernel to be compiled with clang. The announcement reads like being able to compile the kernel with other compilers is a very desirable property, that has taken many years of hard work to achieve due to the incorrect assumption that "GCC is the C standard".

So while that assumption might have made sense back then, it does not appear to make sense now. If you treat one compiler as "the standard", chances are that that's the only compiler that you will ever be able to use. That's a bad strategic decision for a big project like the Linux kernel.

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