Re: 0xdeadbeef vs 0xdeadbeefL

From: tom st denis (tomstdenis_at_yahoo.com)
Date: 07/07/04

  • Next message: Richard B. Johnson: "Re: 0xdeadbeef vs 0xdeadbeefL" 
    Date:	Tue, 6 Jul 2004 17:06:12 -0700 (PDT)
To: linux-kernel@vger.kernel.org

    --- David Eger <eger@havoc.gtf.org> wrote:
    > Is there a reason to add the 'L' to such a 32-bit constant like this?
    > There doesn't seem a great rhyme to it in the headers...

    IIRC it should have the L [probably UL instead] since numerical
    constants are of type ``int'' by default.

    Normally this isn't a problem since int == long on most platforms that
    run Linux. However, by the standard 0xdeadbeef is not a valid unsigned
    long constant.

    Consider the following...

    #include <stdio.h>
    int main(void)
    {
      unsigned int x;
      x = 4;
      if (x < 0xdeadbeef) printf("hello");
      return 0;
    }

    If you run splint on that you get 

    ---
Splint 3.1.1 --- 13 Jun 2004
test2.c: (in function main)
test2.c:7:7: Operands of < have incompatible types (unsigned int, int):
                x < 0xdeadbeef
  To ignore signs in type comparisons use +ignoresigns
Finished checking --- 1 code warning
---
As far as I know splint follows C99 which means that it thinks the
constant is "int".  
Tom
	
		
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  • Next message: Richard B. Johnson: "Re: 0xdeadbeef vs 0xdeadbeefL"

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