RealView Compilation Tools Compiler Reference Guide - ARM ...

Language Extensions
3.4.7 External entities
External entities declared in other scopes are visible.
Errors
The compiler generates a warning if an external entity declared in another scope is
visible.
Example
void f1(void)
{
extern void f();
}
void f2(void)
{
f(); /* Out of scope declaration */
}
3.4.8 Function prototypes
The compiler recognizes function prototypes that override old-style non prototype
definitions that appear at a later position in your code, for example:
Errors
The compiler generates a warning message if you use old-style function prototypes.
Example
int function_prototypes(char);
// Old-style function definition.
int function_prototypes(x)
char x;
{
return x == 0;
}
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