lclint-interest message 193

From evs Fri Feb 20 20:44:18 1998
Date: Fri, 20 Feb 98 19:43:43 -0500
From: evs (David Evans)
To: 100045.1545@compuserve.com
Cc: lclint-interest@larch.lcs.mit.edu, weco@csi.com
In-Reply-To: Hermann Kleier's message of Fri, 20 Feb 1998 22:33:11 +0100 (CET) 
Subject: signal function interface


> I tried to typedef the signal handler function and to use it:
> 
> > typedef void SignalHandlerT (int);
> > void signal (int, SignalHandlerT *);
> > #define SIG_ERR (SignalHandlerT *) -1
>  
> This time the output takes some more lines:
> 
> > LCLint 2.3i --- 15 Sep 97
> >
> > test.c:2,19: Parameter 2 of function signal has inconsistent type:
> >                 declared SignalHandlerT *, specified [function (int)
> > returns void] *
> >  Types are incompatible. (-type will suppress message)
> >   load file posixstrict.lcd: Specification: [function (int) returns
> > void]
> > *
> > test.c: (in macro SIG_ERR)
> > test.c:3,18: Constant SIG_ERR specified as [function (int) returns void]
> > *, but defined as
> >                SignalHandlerT *: (SignalHandlerT *)-1
> >  A function, variable or constant is redefined with a different type.
> > (-incondefs will suppress
> >   message)
> >    load file posixstrict.lcd: Specification of SIG_ERR
> >
> > Finished LCLint checking --- 2 code errors found

This is a bug in the typechecking done by lclint.  It should type check
correctly, the same as when the typedef was not used.  Sorry, I don't
know of any workaround for this, but it'll be fixed in the next release.

> LcLint declares `signal'
> 
> >  void signal (int, void (*) (int));
> 
> to be a function taking a signal number and a pointer to a signal handler
> and RETURNING NOTHING.  What about checking the successfull installation
> of signal handlers?  ANSI C declares signal
> 
> > void (*signal (int sig, void (*func) (int)))(int);

This is also a bug!  The standard library (ansi.h) declares it
correctly, but there is a bug in lclint that prevents it from reporting
ignored return values for functions returning functions that return
void.

Thanks for reporting the problems,

--- Dave