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* [Bug manual/7003] New: description of maximum value of random and random_r
@ 2008-11-04 11:29 bruno at clisp dot org
  2008-11-04 11:31 ` [Bug manual/7003] " bruno at clisp dot org
  2008-11-06 15:46 ` rjones at redhat dot com
  0 siblings, 2 replies; 3+ messages in thread
From: bruno at clisp dot org @ 2008-11-04 11:29 UTC (permalink / raw)
  To: glibc-bugs

The description of the function random (and random_r later on that page says that
"The value returned ranges from 0 to RAND_MAX."

POSIX <http://www.opengroup.org/susv3/functions/random.html> says that the
value ranges from 0 to 2^{31}-1. So glibc's statement is right for glibc systems,
where RAND_MAX == 2^{31}-1. But it tricks programmers into writing code like

  double from_0_to_1 = (double) random () / ((double) RAND_MAX + 1.0);

where

  double from_0_to_1 = (double) random () / 2147483648.0;

would be correctly portable to other POSIX systems.

Find attached a doc fix.

-- 
           Summary: description of maximum value of random and random_r
           Product: glibc
           Version: 2.8
            Status: NEW
          Severity: normal
          Priority: P2
         Component: manual
        AssignedTo: roland at gnu dot org
        ReportedBy: bruno at clisp dot org
                CC: glibc-bugs at sources dot redhat dot com
 GCC build triplet: i686-suse-linux-gnu
  GCC host triplet: i686-suse-linux-gnu
GCC target triplet: i686-suse-linux-gnu


http://sourceware.org/bugzilla/show_bug.cgi?id=7003

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* [Bug manual/7003] description of maximum value of random and random_r
  2008-11-04 11:29 [Bug manual/7003] New: description of maximum value of random and random_r bruno at clisp dot org
@ 2008-11-04 11:31 ` bruno at clisp dot org
  2008-11-06 15:46 ` rjones at redhat dot com
  1 sibling, 0 replies; 3+ messages in thread
From: bruno at clisp dot org @ 2008-11-04 11:31 UTC (permalink / raw)
  To: glibc-bugs


------- Additional Comments From bruno at clisp dot org  2008-11-04 11:29 -------
Created an attachment (id=3040)
 --> (http://sourceware.org/bugzilla/attachment.cgi?id=3040&action=view)
doc correction


-- 


http://sourceware.org/bugzilla/show_bug.cgi?id=7003

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* [Bug manual/7003] description of maximum value of random and random_r
  2008-11-04 11:29 [Bug manual/7003] New: description of maximum value of random and random_r bruno at clisp dot org
  2008-11-04 11:31 ` [Bug manual/7003] " bruno at clisp dot org
@ 2008-11-06 15:46 ` rjones at redhat dot com
  1 sibling, 0 replies; 3+ messages in thread
From: rjones at redhat dot com @ 2008-11-06 15:46 UTC (permalink / raw)
  To: glibc-bugs



-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rjones at redhat dot com


http://sourceware.org/bugzilla/show_bug.cgi?id=7003

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2008-11-04 11:29 [Bug manual/7003] New: description of maximum value of random and random_r bruno at clisp dot org
2008-11-04 11:31 ` [Bug manual/7003] " bruno at clisp dot org
2008-11-06 15:46 ` rjones at redhat dot com

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