Re: cross-platform thread-safe RNG drand48_r

[Ian Lance Taylor <iant at google dot com>]

Qianqian Fang <fangqq@gmail.com> writes:

> On 06/06/2010 11:37 PM, Ian Lance Taylor wrote:
>>
>> As far as I know drand48 is not in POSIX.  It's in the SVID and it's
>> in X/Open, but I don't think it's in POSIX proper.  And as far as I
>> know drand48_r is just a GNU extension to drand48.  But it's certainly
>> possible that POSIX picked this up somewhere.
>>    
>
> thanks for the quick response. I have a silly question though:
> which standard are supposed to be supported by ggc of all
> platforms? POSIX? SVID? c99?

gcc is only a compiler.  It fully supports the C90 standard with
respect to compiler behaviour.  It mostly supports the C99 standard;
exact C99 status can be found at http://gcc.gnu.org/c99status.html .
However, all these standards also specify library behaviour.  gcc does
not include a library.  gcc can be used with a POSIX compliant library
to support a full POSIX compilation environment, but gcc does not
itself provide a POSIX compliant library.

I believe that Windows has a POSIX mode but it is not the usual
Windows programming environment and I don't know how well it works.
As far as I know Mac OS X provides a POSIX library.

Ian