PHP and P++

Posted Aug 17, 2019 16:50 UTC (Sat) by felix.s (guest, #104710)
In reply to: PHP and P++ by iabervon
Parent article: PHP and P++

There are ~7 C standards that GCC supports, rather than being able to mix and match paragraphs from different standards.

You mean, like you can with -fno-delete-null-pointer-checks, -fstrict-aliasing, -f{w,t}rapv, -fgnu89-inline, -fms-extensions, -f{un,}signed-char, -fno-asm, and so on? And let's not forget __attribute__((optimize))…

Sure, these aren't strictly the same thing; ISO C standards are designed to be largely forward-compatible (portable C89 code free of UB can be usually compiled as C11 with no changes), so you'll have a hard time finding cases where the different versions of the standard flat-out contradict each other, creating incompatible dialects. But these options do change how compiler handles certain specific situations that are implementation-defined or UB according to the standard, and some code does depend on one dialect or the other.