Prototyping char parameters in ANSI C

[Doug Schmidt]

In article <3950014 at eecs.nwu.edu> gore at eecs.nwu.edu (Jacob Gore) writes:
++ Is this valid ANSI C (or dpANS or whatever you want to call it):
++ 
++ 	void f(char);
++ 
++ 	void f(c)
++ 	   char c;
++ 	{
++ 	}
++ 
++ The version of GNU cc I have complains:
++ 
++ 	t.c: In function f:
++ 	t.c:5: argument `c' doesn't match function prototype
++ 	t.c:5: a formal parameter type that promotes to `int'
++ 	t.c:5: can match only `int' in the prototype
++ 
++ Is this rule for real, or is this just a gcc bug?

This is a real rule.  Read the GNU C documentation:

----------------------------------------
Users often think it is a bug when GNU CC reports an error for code
like this:
 
int foo (short);
  
int foo (x)
       short x;
{
}        

The error message is correct: this code really is erroneous, because
the old-style non-prototype definition passes subword integers in
their promoted types.  In other words, the argument is really an
int, not a short.  The correct prototype is this:
 
int foo (int);
----------------------------------------  

Doug
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