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Language Extensions
3.4 Standard C language extensions
The compiler supports numerous extensions to the ISO C99 standard, for example,
function prototypes that override old-style non prototype definitions.
These extensions are available if:
• the source language is C99 and you are compiling in non strict mode
• the source language is C90 and you are compiling in non strict mode.
None of these extensions is available if:
• the source language is C90 and the compiler is restricted to compiling strict C90
using the --strict compiler option.
• the source language is C99 and the compiler is restricted to compiling strict
Standard C using the --strict compiler option.
• the source language is C++.
3.4.1 Constant expressions
Extended constant expressions are supported in initializers. The following examples
show the compiler behavior for the default, --strict_warnings, and --strict compiler
modes.
Example 1, assigning the address of variable
Your code might contain constant expressions that assign the address of a variable at file
scope, for example:
int i;
int j = (int)&i; /* but not allowed by ISO */
When compiling for C, this produces the following behavior:
• In default mode a warning is produced.
• In --strict_warnings mode a warning is produced.
• In --strict mode, an error is produced.
Example 2, constant value initializers
The compiler behavior when you have expressions that include constant values in C
code is summarized in the following example:
/* Std RVCT v3.1 */
extern int const c = 10; /* ok ok */
extern int const x = c + 10; /* error ext */
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