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Re: size of a datatype

  • Subject: Re: size of a datatype
  • From: Roy Schestowitz <newsgroups@xxxxxxxxxxxxxxx>
  • Date: Sun, 14 May 2006 04:16:28 +0100
  • Newsgroups: comp.os.linux.advocacy
  • Organization: schestowitz.com / MCC / Manchester University
  • References: <1147499965.060218.303410@i40g2000cwc.googlegroups.com> <40egj3-uju.ln1@ridcully.fsnet.co.uk> <1147506449.314246.192970@j73g2000cwa.googlegroups.com> <bto9g.1919$x4.378@newsread3.news.pas.earthlink.net> <Srq9g.68749$wl.13434@text.news.blueyonder.co.uk>
  • Reply-to: newsgroups@xxxxxxxxxxxxxxx
  • User-agent: KNode/0.7.2
__/ [ M ] on Saturday 13 May 2006 20:28 \__

> Tim Smith wrote:
>> In article <1147506449.314246.192970@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>, sonu
>> wrote:
>>> i wrote like
>>> main()
>>> {
>>>  guint64 x=0xffffffffffffffff
>>> printf("%15d",x);
>>> }
>>> But it is showing warning integer constant is too large for  "long"
>>> type
>> First, next time paste in your exact code.  The code you gave above is
>> missing a semicolon, and so will give more errors than what you listed.
>> Second, next time show the exact and complete error message.  If you had
>> shown:
>>     a.c:3: warning: integer constant is too large for "long" type
>> instead of just paraphrasing it, then the other three people who have
>> already tried to help you would have realized the error is about the
>> assignment line (line 3), and not the printf line.  You've wasted their
>> time and yours because they are focusing on the possible error in the
>> printf format you are using, which has nothing to do with your error you
>> are actually asking about.
>> (That's not to say the printf line is without error, so do keep the other
>> responses in mind after you get past the error you were asking about, as
>> they will be helpful with the error you are going to then run into).
>> Now, on to the problem.  You need to tell it that your constant is
>> supposed
>> to be 64-bits.  How you do this depends on the compiler, I believe, as
>> this
>> is not part of standard C.  For this particular compiler, try sticking a
>> suffix of "LL" on the constant:
>>     guint64 x = 0xffffffffffffffffLL;
>> I have not been able to directly test this, because my gcc does not
>> recognize guint64.  However, if I do this:
>>     long long x = 0xffffffffffffffff;
>> I get the same error you got, and if I do this:
>>     long long x = 0xffffffffffffffffLL;
>> the error goes away.
>> (And if guint64 is a typedef that is coming from some header file you are
>> including, you should have included the #include in the code you posted).
> I haven't got any access to 64 bit machines *yet*, so I haven't needed to
> do anything like that. However I will keep that one in my back pocket :-)
> Wounder if they will change the suffix if and when we ever go to 128 bit
> machines.

,----[ Quote ]
| System/370, made by IBM, is possibly considered the first rudimentary
| 128-bit computer as it used 128-bit floating point registers. Most
| modern CPUs such as the Pentium and PowerPC have 128-bit vector
| registers used to store several smaller numbers, such as 4 32-bit
| floating-point numbers. A single instruction can operate on all these
| values in parallel (SIMD). They are 128-bit processors in the sense that
| they have registers 128 bits wide?they load and store memory in units of
| 128 bits?but they do not operate on single numbers that are 128 binary
| digits in length.

                Source: http://en.wikipedia.org/wiki/128-bit

Can't wait 'till the kilobit processor. Imagine the compexity of the chip and
the compiler...

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