NetNews Usenet Archive 1992 #30/NN_1992_30.iso/spool/comp/std/c/3213

Text File | 1992-12-15 | 1.6 KB | 39 lines

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From: [e-mail] (Natuerlich!)
Subject: Re: Is INT_MAX<<1 defined?
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Date: Tue, 15 Dec 1992 14:21:03 GMT
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Just to raise the voice of one practicing programmer, who doesn't have the
standard at hand. What I expect to happen in expressions like these

    INT_MAX << 1

is that the compiler behaves as if it were ultralame. It acts as if it doesn't
precompute at compiletime but rather computes the result at runtime. So that
in fact the default type for INT_MAX is signed int (since there isn't an U
or an L anywhere) and the shifting operation operates on a signed int on that
system. For a 68000 I'd expect something that produces the same result
as this (lame) code:

    MOVE.L    #INTMAX,d0
    ASL.L    #1,d0

Obviously this may be non-portable, but so what ? If you want portability
you write  (long) INT_MAX * 2 (or somesuch).

To me any other interpretation (even if in the standard) obscures the
C language. If you want to get a long out of INT_MAX << 1 then cast it.

Nat!
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