[Rd] gfortran 9 quantreg bug

[Dirk Eddelbuettel]

Hi Kasper,

On 6 August 2019 at 10:33, Kasper Daniel Hansen wrote:
| Thanks for the blog post on this, and the pointers in this email.

My pleasure!  There wasn't much in there that was "new" but it often helps to
just tie it together with a valid and real example (as provided by Roger).
 
| I have a question: it seems to me that you end up using a different
| compiler for the package (quantreg) than was used to build R itself. As I
| understand ABI changes, this is considered unsupported (ok, that depends on

Are you thinking that because the 'number' increased to 9, the ABI must have
changed in some (presumably incompatible) ways?  Luckily that is not
generally the case or we'd be in much dire straits.

Every couple of years there is such a change but it is rare. I can't even
recall when g++ last forced us.  May have been the 3.3 to 4.0 change with 3.4
then providing compatibility with what came after. As for Fortran, can't
recall such a change.

| what version of gcc/gfortran was used to build R, but there has been a lot
| of ABI changes in GCC). Is that correct? I understand that this shortcut
| makes it much easier to use different compilers, and might work for Roger's
| usecase, but I was wondering about this issue of using a different compiler
| for packages. Is this something I should worry about?

No.

But don't take my word for it, but trust 'R CMD check'. If it tests, trust it.

Hth, Dirk

-- 
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