Using rand_r and -std=c99 with gcc

Using rand_r and -std=c99 with gcc

[Jason Gross]

Hi,
If I try to compile a C program which uses rand_r with gcc 4.5.3, with
-std=c99, I get

warning: implicit declaration of function 'rand_r'.

Google gave me http://cygwin.com/ml/cygwin/2009-05/msg00417.html and
http://sourceware.org/ml/newlib/2007/msg00800.html, which explains why
this happens, but these messages are 3 years old.  Additionally,
http://linux.die.net/man/3/rand_r suggests that rand_r is c99.  Are
there plans to update stdlib.h to account for c99?  If I look through
the http://linux.die.net/man pages and figure out which things are c99
and submit a patch, will it get checked in?

Thanks.

-Jason

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Re: Using rand_r and -std=c99 with gcc

[Larry Hall (Cygwin)]

On 9/6/2012 10:37 PM, Jason Gross wrote:
> Hi,
> If I try to compile a C program which uses rand_r with gcc 4.5.3, with
> -std=c99, I get
>
> warning: implicit declaration of function 'rand_r'.
>
> Google gave me http://cygwin.com/ml/cygwin/2009-05/msg00417.html and
> http://sourceware.org/ml/newlib/2007/msg00800.html, which explains why
> this happens, but these messages are 3 years old.  Additionally,
> http://linux.die.net/man/3/rand_r suggests that rand_r is c99.  Are
> there plans to update stdlib.h to account for c99?  If I look through
> the http://linux.die.net/man pages and figure out which things are c99
> and submit a patch, will it get checked in?

The Linux man page you point to has this to say about rand_r's conformance:

   The function rand_r() is from POSIX.1-2001. POSIX.1-2008 marks rand_r() 
as obsolete.

The fact that rand_r doesn't list c99 and is obsoleted in POSIX.1-2008
makes me dubious that newlib folks are going to jump at a patch to add
it to c99.

-- 
Larry

_____________________________________________________________________

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