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From: hascall@atanasoff.cs.iastate.edu (John Hascall)
Newsgroups: comp.lang.c
Subject: Re: checking for overflow in C
Message-ID: <1079@atanasoff.cs.iastate.edu>
Date: 10 May 89 13:53:05 GMT
References: <13367@dartvax.Dartmouth.EDU> <1989May6.224226.22085@utzoo.uucp> <1989May9.183140.1770@utzoo.uucp> <8172@june.cs.washington.edu>
Reply-To: hascall@atanasoff.cs.iastate.edu (John Hascall)
Organization: Iowa State Univ. Computation Center
Lines: 30

In article <8172@june.cs.washington.edu> ka@june.cs.washington.edu (Kenneth Almquist) writes:
>In article <1989May9.183140.1770@utzoo.uucp>, henry@utzoo.uucp (Henry Spencer) writes:
>> In article <8143@june.cs.washington.edu> ka@june.cs.washington.edu (Kenneth Almquist) writes:
 
>OK, I think I see your point.  My assumption is that the cost isn't a
>big issue because the programmer wouldn't test for overflow unless it
>was necessary.  You would see an *occasional* test such as:
 
>	  new C keyword
>		|
>		v
>	if (overflow a = b * c)
>		printf("Multiplication overflowed\n");
>	else
>		printf("%d * %d = %d\n", b, c, a);
 

     Oh, help us please!!!!

     What are you people trying to do?  Turn C into PL/1?

     If this overflow business is important to you (and it certainly is
     for some)...  Why not use SIGFPE?  This works (is documented to work,
     I've never had occasion to try it) under BSD on the VAX, perhaps
     it works on your machine as well.  Did ANSI have anything to say
     on this topic?


     John Hascall
     ISU Comp Center