有没有不支持ANSI C 89的平台？

Question

It seems ANSI C 89 is the best choise for writing a cross-platform library because many platforms (Windows, Unix, Linux, Mac, Android, ...) supports it.

But is there any platform that not supports ANSI C 89?

I am not sure about J2ME, iPhone and so on..

Answer 1

First, ANSI C usually refers to C89, so the C89 is redundant.

iOS supports ANSI C, as well as most of the platforms. J2ME is a Java platform and by default it does not support C at all.

The main platforms all support ANSI C, but there are some embedded platforms that does not. I don't think you should be worried about any of those.

Answer 2

Any platform that has too little memory either for code or for data does not support C. As mandated by the standard in section "2.2.4.1 Translation limits":

The implementation shall be able to translate and execute at least one program that contains at least one instance of every one of the following limits:

• 15 nesting levels of compound statements, iteration control
  structures, and selection control structures

• 8 nesting levels of conditional inclusion

• 12 pointer, array, and function declarators (in any combinations)
  modifying an arithmetic, a structure, a union, or an incomplete type
  in a declaration

• 31 declarators nested by parentheses within a full declarator

• 32 expressions nested by parentheses within a full expression

...

• 127 identifiers with block scope declared in one block

...

• 31 parameters in one function definition

• 31 arguments in one function call

...

• 509 characters in a character string literal or wide string literal (after concatenation)

• 32767 bytes in an object (in a hosted environment only)

...

• 127 members in a single structure or union

...

• 15 levels of nested structure or union definitions in a single
  struct-declaration-list

You will likely find other requirements if you read the standard with attention.

In the end, if there's enough memory, even an otherwise weak platform can support C. It will have to have extra code to overcome the hardware limitations (eg support the required types, arithmetic operations and so on).