On changing rand(3) to random(3) in awk(1)

[Peter Pentchev]

On Thu, Aug 28, 2014 at 12:51:52PM +0300, Vitaly Magerya wrote:
> On 2014-08-28 09:21, Chenguang Li wrote:
[snip]
> >Index: run.c
> >===================================================================
> >--- run.c       (revision 270740)
> >+++ run.c       (working copy)
> >@@ -1522,7 +1522,7 @@
> >                break;
> >        case FRAND:
> >                /* in principle, rand() returns something in 0..RAND_MAX */
> >-               u = (Awkfloat) (rand() % RAND_MAX) / RAND_MAX;
> >+               u = (Awkfloat) (random() % RAND_MAX) / RAND_MAX;
> 
> You should not use RAND_MAX with random(3), since it returns values
> between 0 and 0x7fffffff (inclusive); RAND_MAX only applies to rand(3).
> 
> A better patch would be something like this:
> 
> >-               /* in principle, rand() returns something in 0..RAND_MAX */
> >-               u = (Awkfloat) (rand() % RAND_MAX) / RAND_MAX;
> >+               /* random() returns values in [0, 2147483647] */
> >+               u = (Awkfloat) random() / 2147483648;

Hm.  Since random() is documented to return "long", wouldn't it be a bit
better with #include <limits.h> and LONG_MAX here?

G'luck,
Peter

-- 
Peter Pentchev  roam at ringlet.net roam at FreeBSD.org p.penchev at storpool.com
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