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Add header to declare C level API #4645

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Merged
mattdowle merged 1 commit into from
Aug 4, 2020
Merged

Add header to declare C level API #4645

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45 changes: 45 additions & 0 deletions inst/include/datatableAPI.h
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Original file line number Diff line number Diff line change
@@ -0,0 +1,45 @@

/* This header file provides the interface used by other packages,
and should be included once per package. */

#ifndef _R_data_table_API_h_
#define _R_data_table_API_h_

/* number of R header files (possibly listing too many) */
#include <R.h>

#ifdef HAVE_VISIBILITY_ATTRIBUTE
# define attribute_hidden __attribute__ ((visibility ("hidden")))
#else
# define attribute_hidden
#endif

#ifdef __cplusplus
extern "C" {
#endif

/* provided the interface for the function exported in
../src/init.c via R_RegisterCCallable() */

SEXP attribute_hidden DT_subsetDT(SEXP x, SEXP rows, SEXP cols) {
static SEXP(*fun)(SEXP, SEXP, SEXP) =
(SEXP(*)(SEXP,SEXP,SEXP)) R_GetCCallable("data.table", "CsubsetDT");
return fun(x,rows,cols);
Comment on lines +25 to +27
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@jangorecki jangorecki Oct 12, 2020 •
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@eddelbuettel is it necessary to create fun object here? couldn't this be a one liner to returning R_GetCCallable() call?

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@eddelbuettel eddelbuettel Oct 12, 2020

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Yes: fun is what is invoked when you call. The static makes the assignment stick, and the R_GetCCallable() ges the identifier from the other package.

}

/* permit opt-in to redefine shorter identifiers */
#if defined(DATATABLE_REMAP_API)
#define subsetDT DT_subsetDT
#endif

#ifdef __cplusplus
}

/* add a namespace for C++ use */
namespace dt {
inline SEXP subsetDT(SEXP x, SEXP rows, SEXP cols) { return DT_subsetDT(x, rows, cols); }
}

#endif /* __cplusplus */

#endif /* _R_data_table_API_h_ */