From ripley at stats.ox.ac.uk  Sun Jan  1 14:28:48 2017
From: ripley at stats.ox.ac.uk (Prof Brian Ripley)
Date: Sun, 1 Jan 2017 13:28:48 +0000
Subject: [Rd] Definition of uintptr_t in Rinterface.h
In-Reply-To: <3ECD3048-DC04-467B-BD33-787A4E70FE67@r-project.org>
References: <CA+JCgN0pwwmtPZ+p4Yf2fi1uXb2r-0H1jD+hOj1iWi58EiO-_A@mail.gmail.com>
	<3ECD3048-DC04-467B-BD33-787A4E70FE67@r-project.org>
Message-ID: <ebab4eb6-e739-badb-1af1-ffc77bbb5847@stats.ox.ac.uk>

On 29/12/2016 15:55, Simon Urbanek wrote:
> The problem is elsewhere - Rinterface.h guards the ultima-ratio fallback with HAVE_UINTPTR_T but that config flag is not exported in Rconfig.h. Should be now fixed in R-devel - please check if that works for you.

Rconfig.h would be appropriate if Rinterface.h is being included from C 
code using the same compiler as used for R.  But as Rinterface.h is 
intended for use by alternative front ends there is no guarantee that 
they use the same compiler (and some use C++).

This was documented in the manual:

'Note that uintptr_t is a C99 type for which a substitute is defined in 
R, so your code needs to define HAVE_UINTPTR_T appropriately.'

AFAICS if you comply, there will not be a conflict.

Also note that is only an issue if CSTACK_DEFNS is defined, not the 
default and not mentioned here.



> Thanks,
> Simon
>
>
>
>> On Dec 26, 2016, at 11:25 PM, Laurent Gautier <lgautier at gmail.com> wrote:
>>
>> Hi,
>>
>> I was recently pointed out that a definition in Rinterface.h can be conflicting
>> with a definition in stdint.h:
>>
>> /usr/include/R/Rinterface.h has:
>> typedef unsigned long uintptr_t;
>>
>> /usr/include/stdint.h has:
>> typedef unsigned int uintptr_t;
>> (when 32bit platform complete definition is:
>>
>> #if __WORDSIZE == 64
>> # ifndef __intptr_t_defined
>> typedef long int                intptr_t;
>> #  define __intptr_t_defined
>> # endif
>> typedef unsigned long int       uintptr_t;
>> #else
>> # ifndef __intptr_t_defined
>> typedef int                     intptr_t;
>> #  define __intptr_t_defined
>> # endif
>> typedef unsigned int            uintptr_t;
>> #endif
>>
>> )
>>
>> Is this expected ? Shouldn't R rely on the definition in stdint.h

But there need not be one in stdint.h, as the type is optional in 
C99/C11/C++11 and likely not present in C++98.

>> rather than define its own ?
>>
>>
>> (report for the issue:
>> https://bitbucket.org/rpy2/rpy2/issues/389/failed-to-compile-with-python-360-on-32
>> )
>>
>>
>> Laurent
>>


-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Emeritus Professor of Applied Statistics, University of Oxford



[Rd] Definition of uintptr_t in Rinterface.h
Prof Brian Ripley