Re: ZeroLink: Perhaps better disabled per default?
Re: ZeroLink: Perhaps better disabled per default?
- Subject: Re: ZeroLink: Perhaps better disabled per default?
- From: Andreas Grosam <email@hidden>
- Date: Fri, 14 Oct 2005 13:18:10 +0200
On 14.10.2005, at 06:53, Marshall Clow wrote:
At 2:41 AM +0200 10/14/05, Andreas Grosam wrote:
While I fully agree with j o a r, I would like to mention, that this code snippet will compile without errors:
// file: foo.c
extern void bar(); // prototype
void foo() {
boar(); // typo
}
Don't expect errors when compiling with a C compiler. It even will not complain when the -pedantic or -Wmissing-prototypes flags are on.
This is because it is completely valid and legal code.
Sure, it won't link.
This may be true with gcc, but I have used C compilers (since the early 1990s) that would complain if they saw a routine that they had not previously seen a declaration or prototype for. (This behavior was controlled by a compiler switch, usually called "Require function prototypes" or something similar.)
This was not a CodeWarrior-ism, it predates CodeWarrior.
GNU C has a similar warning:
-Wmissing-prototypes (C only)
Warn if a global function is defined without a previous prototype declaration. This warning is issued even if the definition itself provides a prototype. The aim is to detect global functions that fail to be declared in header files.
This warning does not apply here, because within the function foo() a function will be *called* ( boar()) but not defined.
You see the differences?
Actually, the above code is valid and legal - its behavior is clearly defined in the C standard.
In C there is no warning flags which detects such usage. The linker will issue an error because of an undefined symbol _boar.
Maybe an improved indexer and (known) symbol coloring in Xcode may detect this errors.
Andreas
--
-- Marshall
Marshall Clow Idio Software <mailto:email@hidden>
It is by caffeine alone I set my mind in motion.
It is by the beans of Java that thoughts acquire speed,
the hands acquire shaking, the shaking becomes a warning.
It is by caffeine alone I set my mind in motion.
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