ID Number: Q66776
6.00 6.00a 6.00ax 7.00 | 6.00 6.00a
MS-DOS | OS/2
Summary:
In situations where the so-called "old-style" or "K&R-type" function
declarations are used, the C compiler will not generate a warning when
formal parameters are declared twice, even if they are redeclared with
different types. This is expected behavior because one of the
declarations is ignored when this type of function declaration is
used. If ANSI-style, prototyped function declarations are used, a
warning will be generated for any redeclarations.
More Information:
The following code sample demonstrates this redeclaration problem:
int func1(x, y)
int x;
long y;
float x; /* x is redeclared here, but no warning is given */
{
return (int)(x + y);
}
Even when this code is compiled at warning level 4 (/W4), the
redeclaration of x does not generate any warnings -- the compiler only
warns that func1() is using an old-style function declarator.
Microsoft is committed to the ANSI standard and no diagnostic-message
changes are planned to accommodate inconsistencies arising from use of
the old declaration style. The ANSI specification, in Section 3.9.5,
page 96, states the following:
The use of function definitions with separate parameter identifier
and declaration lists (not prototype-format parameter type and
identifier declarators) is an obsolescent feature.
Additional reference words: 6.00 6.00a 6.00ax 7.00 S_QUICKC