R devel - Oct 2018 - R_ext/Altrep.h should be more C++-friendly

I am not able to #include "R_ext/Altrep.h" from a C++ file.  I think
it needs two changes:

1. add the same __cplusplus check as most of the other header files:
    #ifdef  __cplusplus
    extern "C" {
    #endif
        ...
    #ifdef  __cplusplus
    }
    #endif

2. change the line
    R_new_altrep(R_altrep_class_t class, SEXP data1, SEXP data2);
 to
    R_new_altrep(R_altrep_class_t cls, SEXP data1, SEXP data2);
 since C++ doesn't like an argument named 'class'

  ~~ Michael Sannella

	[[alternative HTML version deleted]]

Thanks for the suggestion. Committed in R_devel.

Best,

luke

On Mon, 8 Oct 2018, Michael Sannella wrote:
> I am not able to #include "R_ext/Altrep.h" from a C++ file.? I
think
> it needs two changes:
> 
> 1. add the same __cplusplus check as most of the other header files:
> ? ? #ifdef? __cplusplus
> ? ? extern "C" {
> ? ? #endif
> ? ? ? ? ...
> ? ? #ifdef? __cplusplus
> ? ? }
> ? ? #endif
> 
> 2. change the line
> ? ? R_new_altrep(R_altrep_class_t class, SEXP data1, SEXP data2);
> ?to
> ? ? R_new_altrep(R_altrep_class_t cls, SEXP data1, SEXP data2);
> ?since C++ doesn't like an argument named 'class'
> 
> ? ~~ Michael Sannella
> 
> 
>
-- 
Luke Tierney
Ralph E. Wareham Professor of Mathematical Sciences
University of Iowa                  Phone:             319-335-3386
Department of Statistics and        Fax:               319-335-3017
    Actuarial Science
241 Schaeffer Hall                  email:   luke-tierney at uiowa.edu
Iowa City, IA 52242                 WWW:  http://www.stat.uiowa.edu

Michael,

Thanks for reaching out. This was brought up by Romaine Francois offline to
me as well. What he does as a workaround is


#define class klass
extern "C" {
  #include <R_ext/Altrep.h>
}
#undef class

While we consider changing Altrep.h, the above should work for you  in the
immediate term.

Let me know if it doesn't.

~G





On Mon, Oct 8, 2018 at 4:17 PM, Michael Sannella via R-devel <
r-devel at r-project.org> wrote:
> I am not able to #include "R_ext/Altrep.h" from a C++ file.  I
think
> it needs two changes:
>
> 1. add the same __cplusplus check as most of the other header files:
>     #ifdef  __cplusplus
>     extern "C" {
>     #endif
>         ...
>     #ifdef  __cplusplus
>     }
>     #endif
>
> 2. change the line
>     R_new_altrep(R_altrep_class_t class, SEXP data1, SEXP data2);
>  to
>     R_new_altrep(R_altrep_class_t cls, SEXP data1, SEXP data2);
>  since C++ doesn't like an argument named 'class'
>
>   ~~ Michael Sannella
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>
>

-- 
Gabriel Becker, Ph.D
Scientist
Bioinformatics and Computational Biology
Genentech Research

	[[alternative HTML version deleted]]

I successfully use this workaround in this package:
https://github.com/romainfrancois/altrepisode

(which is just my way to get familiar with altrep, nothing serious)
> Le 9 oct. 2018 ? 17:00, Gabe Becker <becker.gabe at gene.com> a ?crit
:
> 
> Michael,
> 
> Thanks for reaching out. This was brought up by Romaine Francois offline to
me as well. What he does as a workaround is
> 
> 
> #define class klass
> extern "C" {
>   #include <R_ext/Altrep.h>
> }
> #undef class
> 
> While we consider changing Altrep.h, the above should work for you  in the
immediate term.
> 
> Let me know if it doesn't.
> 
> ~G
> 
> 
> 
> 
> 
>> On Mon, Oct 8, 2018 at 4:17 PM, Michael Sannella via R-devel
<r-devel at r-project.org> wrote:
>> I am not able to #include "R_ext/Altrep.h" from a C++ file. 
I think
>> it needs two changes:
>> 
>> 1. add the same __cplusplus check as most of the other header files:
>>     #ifdef  __cplusplus
>>     extern "C" {
>>     #endif
>>         ...
>>     #ifdef  __cplusplus
>>     }
>>     #endif
>> 
>> 2. change the line
>>     R_new_altrep(R_altrep_class_t class, SEXP data1, SEXP data2);
>>  to
>>     R_new_altrep(R_altrep_class_t cls, SEXP data1, SEXP data2);
>>  since C++ doesn't like an argument named 'class'
>> 
>>   ~~ Michael Sannella
>> 
>>         [[alternative HTML version deleted]]
>> 
>> ______________________________________________
>> R-devel at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-devel
>> 
> 
> 
> 
> -- 
> Gabriel Becker, Ph.D
> Scientist
> Bioinformatics and Computational Biology
> Genentech Research
	[[alternative HTML version deleted]]

Thank you, 

I updated my example package so that it works with both.
https://github.com/romainfrancois/altrepisode/blob/96af0548a9ecc08701d119ea427e16940a82882b/src/altrepisode.h
<https://github.com/romainfrancois/altrepisode/blob/96af0548a9ecc08701d119ea427e16940a82882b/src/altrepisode.h>

We have to do something like this unless we depend on R 3.6.0: 

#if R_VERSION < R_Version(3, 6, 0)
  #define class klass
  extern "C" {
    #include <R_ext/Altrep.h>
  }
  #undef class
#else
  #include <R_ext/Altrep.h>
#endif

Romain
> Le 9 oct. 2018 ? 05:09, Tierney, Luke <luke-tierney at uiowa.edu> a
?crit :
> 
> Thanks for the suggestion. Committed in R_devel.
> 
> Best,
> 
> luke
> 
> On Mon, 8 Oct 2018, Michael Sannella wrote:
> 
>> I am not able to #include "R_ext/Altrep.h" from a C++ file. 
I think
>> it needs two changes:
>> 
>> 1. add the same __cplusplus check as most of the other header files:
>>     #ifdef  __cplusplus
>>     extern "C" {
>>     #endif
>>         ...
>>     #ifdef  __cplusplus
>>     }
>>     #endif
>> 
>> 2. change the line
>>     R_new_altrep(R_altrep_class_t class, SEXP data1, SEXP data2);
>>  to
>>     R_new_altrep(R_altrep_class_t cls, SEXP data1, SEXP data2);
>>  since C++ doesn't like an argument named 'class'
>> 
>>   ~~ Michael Sannella
>> 
>> 
>> 
> 
> -- 
> Luke Tierney
> Ralph E. Wareham Professor of Mathematical Sciences
> University of Iowa                  Phone:             319-335-3386
> Department of Statistics and        Fax:               319-335-3017
>    Actuarial Science
> 241 Schaeffer Hall                  email:   luke-tierney at uiowa.edu
> Iowa City, IA 52242                 WWW:  http://www.stat.uiowa.edu
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel

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