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Language Extensions
3.2 C99 language features available in C90
The compiler supports numerous extensions to the ISO C90 standard, for example,
C99-style // comments.
These extensions are available if the source language is C90 and you are compiling in
non strict mode.
These extensions are not available if the source language is C90 and the compiler is
restricted to compiling strict C90 using the --strict compiler option.
Note
Language features of Standard C and Standard C++, for example C++-style //
comments, might be similar to the C90 language extensions described in this section.
Such features continue to remain available if you are compiling strict Standard C or
strict Standard C++ using the --strict compiler option.
3.2.1 // comments
The character sequence // starts a one line comment, like in C99 or C++.
// comments in C90 have the same semantics as // comments in C99.
Example
// this is a comment
See also
• New features of C99 on page 5-45 in the Compiler User Guide.
3.2.2 Subscripting struct
In C90, arrays that are not lvalues still decay to pointers, and can be subscripted.
However, you must not modify or use them after the next sequence point, and you must
not apply the unary & operator to them. Arrays of this kind can be subscripted in C90,
but they do not decay to pointers outside C99 mode.
Example
struct Subscripting_Struct
{
int a[4];
};
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