Compiler support for C99

C99 feature	Paper(s)	GCC	Clang	MSVC	Apple Clang	EDG eccp	Intel C++	IBM XL C++	IBM Open XL C++ for AIX	IBM Open XL C++ for z/OS	Sun/Oracle C++	Embarcadero C++ Builder	Cray	Nvidia HPC C++ (ex PGI)*	Nvidia nvcc
Universal-character-names in identifiers	N/A	3.1	Yes	Yes
Increased translation limits	N590	0.9	N/A
// comments	N644	2.7	Yes	Yes
`restrict` pointers	N448	2.95	Yes	partial*
Enhanced arithmetic types	N815 N601 N620 N638 N657 N694 N809	Yes	partial	Maybe
Flexible array members	N/A	3.0	Yes	Yes
Variable-length array (VLA) types	N683	0.9	Yes
Variably-modified (VM) types	N2778	N/A	Yes
Designated initializers	N494	3.0	Yes	Yes
Non-constant initializers	N/A	1.21	N/A
Idempotent cvr-qualifiers	N505	3.0	N/A
Trailing comma in enumerator-list	N/A	0.9	Yes	Yes
Hexadecimal floating constants	N308	2.8	Yes	Yes
Compound literals	N716	3.1	Yes	Yes
Floating-point environment	N/A	partial	partial
Requiring truncation for divisions of signed integer types	N617	0.9	N/A
Implicit return 0; in the `main()` function	N/A	Yes	Yes	Yes
Declarations and statements in mixed order	N740	3.0	Yes	Yes
init-statement in `for` loops	N/A	Yes	Yes	Yes
`inline` functions	N741	4.3	Yes	Yes
Predefined variable `__func__`	N611	2.95	Yes	Yes
Cvr-qualifiers and static in [] within function declarations	N/A	3.1	Yes
Variadic macros	N707	2.95	Yes	Yes
`_Pragma` preprocessor operator	N634	3.0	Yes	partial*
Standard pragmas for floating-point evaluation	N631 N696	No	No								Yes
C99 feature	Paper(s)	GCC	Clang	MSVC	Apple Clang	EDG eccp	Intel C++	IBM XL C++	IBM Open XL C++ for AIX	IBM Open XL C++ for z/OS	Sun/Oracle C++	Embarcadero C++ Builder	Cray	Nvidia HPC C++ (ex PGI)*	Nvidia nvcc

C99
C23