Warnings when compiling on R 4.2 or lower

[mfansler]

This package uses C++17 syntax, which is declared in the DESCRIPTION file. However, R does not use this information to control the C++ standard, but instead defaults to gnu++14 in R 4.2 and gnu++11 in R 4.1. This results in warnings about C++17 extensions during installation (e.g., see recent CRAN install log¹).

These warnings could be avoided by explicitly setting CXX_STD=CXX17 in Makevars(.win) files.

This is just a minor suggestion (nothing urgent).

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_{[1]: Unfortunately, this is not a persistent log. Specifically, there are two warning: decomposition declarations are a C++17 extension resulting from compiling compression.cpp with -std=gnu++14.}

[elbersb]

Hi! Would a Makevars file in the src directory solve this? Or do I need a Makevars.win file as well?

[mfansler]

Not sure if windows will use the generic one, so might need both.