R changes names of constant

[jarioksa]

Brian Ripley told us:

NEWS for 4.2.0 alpha (and R-devel for months before) has

• The legacy S-compatibility macros DOUBLE_* in R_ext/Constants.h
(included by R.h) are deprecated.

The plan is to remove them in R-devel soon after the release of 4.2.0, so please do so in your package before Apr 23.

The standard C99 constants are those used in that header:

#define DOUBLE_DIGITS DBL_MANT_DIG
#define DOUBLE_EPS DBL_EPSILON
#define DOUBLE_XMAX DBL_MAX
#define DOUBLE_XMIN DBL_MIN

defined in <float.h> or for C++, , so please change to those.

Unfortunately there is no portable way to give a deprecation warning in a header so once these are removed your package will fail to install.

Quick grepping found DOUBLE_XMAX in src/stepacross.c, but there may be other cases.

[jarioksa]

<R.h> defined constant DOUBLE_XMAX but that will be deprecated in R 4.2.x ("were deprecated" according to the file, using past tense for future changes). Instead R will now use DBL_MAX of the compiler. The availability of this depends on the compiler, but with the current R requirements of C99, it should be available. There may be old R versions that do not require (and use!) C99, and the fix may fail there. Instead of commit 3833ad6 the following could work also in these:

/* Instead of replacing DOUBLE_XMAX (R) with DBL_MAX (compiler) of commit 3833ad6: */
#ifndef DOUBLE_XMAX
#define DOUBLE_XMAX DBL_MAX
#endif