If using CXX1XSTD should also use CXX1X compiler

[jimhester]

readxl sets PKG_CXXFLAGS to include CXX1XSTD (added in commit c957ce1), but does not use the CXX1X compiler.

If the user speficies an alternative compiler for CXX1X (and CXX1XSTD) in Makevars this can result in readxl failing to build (see https://travis-ci.org/leeper/rio/builds/131807863#L1641-L1645 for an example).

In addition the comment confuses me, if the issue is compiling C code with the C99 standard as the submission comments suggest, should we not be setting PKG_CFLAGS=-std=c99 instead?

[maxheld83]

as an intermediate fix, @jimhester suggested (if I understood correctly) to amend my ~/.R/Makevarsas per wesm/feather#154.

I tried the below .travis.yaml additions:

before_install: |
    mkdir ~/.R
    cat <<EOF > ~/.R/Makevars
    CXX1X=g++-4.9
    CXX1XSTD=-std=c++11
    echo "CC=gcc-4.9 >>" ~/.R/Makevars

But still got a failing build, this time erroring out on feather again.

Installing feather (0.3.1) ... 
[1] "Command failed (1)\n\nFailed to run system command:\n\n\t'/home/travis/R-bin/lib/R/bin/R' --vanilla CMD INSTALL '/tmp/RtmpsvJQDC/feather' --library='/home/travis/build/maxheld83/goodlife/packrat/lib/x86_64-pc-linux-gnu/3.3.2' --install-tests --no-docs --no-multiarch --no-demo \n\nThe command failed with output:\n* installing *source* package 'feather' ...\n** package 'feather' successfully unpacked and MD5 sums checked\nPlatform is little endian. Good.\n** libs\ng++ -std=c++0x -I/home/travis/R-bin/lib/R/include -DNDEBUG -I. -I/home/travis/R-bin/include -I\"/home/travis/build/maxheld83/goodlife/packrat/lib/x86_64-pc-linux-gnu/3.3.2/Rcpp/include\"   -fpic  -g -O2 -c RcppExports.cpp -o RcppExports.o\nIn file included from feather/api.h:24:0,\n                 from feather_types.h:2,\n                 from RcppExports.cpp:4:\n./feather/common.h:24:28: error: both 'const' and 'constexpr' cannot be used here\n./feather/common.h:25:28: error: both 'const' and 'constexpr' cannot be used here\nIn file included from feather/api.h:25:0,\n                 from feather_types.h:2,\n                 from RcppExports.cpp:4:\n./feather/io.h:73:29: error: expected ';' at end of member declaration\n./feather/io.h:73:35: error: 'override' does not name a type\n./feather/io.h:74:26: error: expected ';' at end of member declaration\n./feather/io.h:74:28: error: 'override' does not name a type\n./feather/io.h:75:59: error: expected ';' at end of member declaration\n./feather/io.h:75:61: error: 'override' does not name a type\n./feather/io.h:93:29: error: expected ';' at end of member declaration\n./feather/io.h:93:35: error: 'override' does not name a type\n./feather/io.h:94:26: error: expected ';' at end of member declaration\n./feather/io.h:94:28: error: 'override' does not name a type\n./feather/io.h:95:59: error: expected ';' at end of member declaration\n./feather/io.h:95:61: error: 'override' does not name a type\n./feather/io.h:108:29: error: expected ';' at end of member declaration\n./feather/io.h:108:35: error: 'override' does not name a type\n./feather/io.h:109:26: error: expected ';' at end of member declaration\n./feather/io.h:109:28: error: 'override' does not name a type\n./feather/io.h:110:59: error: expected ';' at end of member declaration\n./feather/io.h:110:61: error: 'override' does not name a type\n./feather/io.h:150:16: error: expected ';' at end of member declaration\n./feather/io.h:150:18: error: 'override' does not name a type\n./feather/io.h:151:29: error: expected ';' at end of member declaration\n./feather/io.h:151:35: error: 'override' does not name a type\n./feather/io.h:152:51: error: expected ';' at end of member declaration\n./feather/io.h:152:53: error: 'override' does not name a type\n./feather/io.h:172:16: error: expected ';' at end of member declaration\n./feather/io.h:172:18: error: 'override' does not name a type\n./feather/io.h:173:29: error: expected ';' at end of member declaration\n./feather/io.h:173:35: error: 'override' does not name a type\n./feather/io.h:174:51: error: expected ';' at end of member declaration\n./feather/io.h:174:53: error: 'override' does not name a type\nmake: *** [RcppExports.o] Error 1\nERROR: compilation failed for package 'feather'\n* removing '/home/travis/build/maxheld83/goodlife/packrat/lib/x86_64-pc-linux-gnu/3.3.2/feather'"
Error: Command failed (1)

Failed to run system command:

	'/home/travis/R-bin/lib/R/bin/R' --vanilla CMD INSTALL '/tmp/RtmpsvJQDC/feather' --library='/home/travis/build/maxheld83/goodlife/packrat/lib/x86_64-pc-linux-gnu/3.3.2' --install-tests --no-docs --no-multiarch --no-demo 

The command failed with output:
* installing *source* package 'feather' ...
** package 'feather' successfully unpacked and MD5 sums checked
Platform is little endian. Good.
** libs
g++ -std=c++0x -I/home/travis/R-bin/lib/R/include -DNDEBUG -I. -I/home/travis/R-bin/include -I"/home/travis/build/maxheld83/goodlife/packrat/lib/x86_64-pc-linux-gnu/3.3.2/Rcpp/include"   -fpic  -g -O2 -c RcppExports.cpp -o RcppExports.o
In file included from feather/api.h:24:0,
                 from feather_types.h:2,
                 from RcppExports.cpp:4:
./feather/common.h:24:28: error: both 'const' and 'constexpr' cannot be used here
./feather/common.h:25:28: error: both 'const' and 'constexpr' cannot be used here
In file incl
Execution halted


The command "R -e "0" --args --bootstrap-packrat" failed and exited with 1 during .

Your build has been stopped.

Apologies in advance if this is because I am using the makevars wrong.

[maxheld83]

interestingly, just setting dist = trusty also solves the issue, though I am not sure whether that is recommended:

language: r

sudo: false

dist: trusty

install:
  - R -e "0" --args --bootstrap-packrat

warnings_are_errors: false

cache:
  packages: true
  directories:
    - $TRAVIS_BUILD_DIR/_bookdown_files
    - $TRAVIS_BUILD_DIR/packrat/

before_script:
  - chmod +x ./_build.sh
  - chmod +x ./_deploy.sh

script:
  - ./_build.sh
  - ./_deploy.sh

notifications:
  email: false

[jimhester]

The first example creates a HEREDOC, so you just need to add CXX=g++-4.9.

Trusty has an older version of GCC as the default, so doesn't run into this issue.