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From: wirzenius@cc.helsinki.fi (Lars Wirzenius)
Newsgroups: comp.lang.c
Subject: Re: 32 bit longs
Message-ID: <1991Jan25.002522.4645@cc.helsinki.fi>
Date: 25 Jan 91 00:25:22 GMT
References: <14824@smoke.brl.mil> <BEVAN.91Jan12120920@orca.cs.man.ac.uk>  <1991Jan22.022206.24691@tkou02.enet.dec.com>
Distribution: comp
Organization: University of Helsinki
Lines: 20

In article <1991Jan22.022206.24691@tkou02.enet.dec.com>, diamond@jit345.swstokyo.dec.com (Norman Diamond) writes:
> In article <231@nazgul.UUCP> bright@nazgul.UUCP (Walter Bright) writes:
>>
>>If you have a need for *exactly* 32 bits, you can do things like:
>>	if (sizeof(x) == 4)
>>		/* code here depends on 32 bits in x */
> 
> On a machine with 36-bit words and C support hacked with 9-bit chars,
> this test will give an undesired result.

Wouldn't the following work (assuming CHAR_BIT is defined properly), if
the aim is to verify that x has a size of 32 bits:

	if (sizeof(x) * CHAR_BIT == 32)

By the way, is there any guarantee that all bits are used to represent a
value? That is, does a 16-bit unsiged always have a value range of
0..65535?

Lars Wirzenius    wirzenius@cc.helsinki.fi