On 01/04/2021 9:06 p.m., David Cortes wrote:
I’d like to ask for clarification about CRAN policies regarding usage
of functions that start with "RC_*", such as "RC_fopen".
I'm trying to upload a package which is meant for reading and writing
data from text files in a certain format, for which I want to use a C
file pointer which I obtain through "RC_fopen". The R extensions manual
says the following:
"... there are other header files there that can be included too, but
many of the features they contain should be regarded as undocumented
and unstable."
Since "RC_fopen" is present in a header file, I would guess it should
be classified as "public" within the entry points classification
(between API/public/private/hidden). This is the description for such
entry points in the manual:
"Entry points declared in an installed header file that are exported on
all R platforms but are not documented and subject to change without
notice."
As I understand it, there is nothing that would forbid using public
entry points compared to the explicit point made about "private" entry
points. However, when I try to submit the package to CRAN, it doesn't
make it past the automated checks due to a NOTE:
Check: compiled code, Result: NOTE
File 'readsparse/libs/readsparse.so':
Found non-API call to R: 'RC_fopen'
Compiled code should not call non-API entry points in R.
See 'Writing portable packages' in the 'Writing R Extensions' manual.
Is it allowed to use such functions in packages? I see a few packages
currently in CRAN have the same note in the checks, such as "iotools",
and am wondering if I should just email the CRAN maintainer explaining
that I intend to use the function anyway, since it's just a note rather
than a warning or error.
The CRAN policy document is quite clear on this: "CRAN packages should
use only the public API. Hence they should not use entry points not
declared as API in installed headers nor .Internal() nor .Call() etc
calls to base packages. Also, ::: should not be used to access
undocumented/internal objects in base packages (nor should other means
of access be employed). Such usages can cause packages to break at any
time, even in patched versions of R. "
So you are free to use that function, but CRAN won't publish your
package if you do.
Duncan Murdoch
Duncan Murdoch
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