Compiler querying fails with compilers that do not output __STD_VERSION__ by default (gcc <=4.8.x)

[sean-mcmanus]

Hi Colen Garoutte-Carson (@Colengms) I'm having a similar issue, since I updated 1.2.0-insiders the compilerPath in the c_cpp_properties.json doesn't find the compiler, which is in my PATH, Output from C/C++ Warnings:

[15/01/2021, 14:14:45] Unable to resolve configuration with compilerPath "arm-openwrt-linux-gcc".  Using "/usr/bin/clang" instead.
[15/01/2021, 14:14:45] Unable to resolve configuration with compilerPath "arm-openwrt-linux-gcc".  Using "/usr/bin/clang" instead.

Not sure if it was fixed in 1.2.0.

Originally posted by Pedro Oliveira (@pelco) in #6746 (comment)

[Colengms]

Hi Pedro Oliveira (@pelco) . I'm not able to easily repro this. If you specify a compiler path of just "gcc", does that work (assuming gcc is in your env path, which it usually is by default on Linux if installed) ?

[pelco]

Hi, Colen Garoutte-Carson (@Colengms), Yes! It works with "gcc" and "clang" (both are in my path too).

[Colengms]

Hi Pedro Oliveira (@pelco) . Ok, that would seem to imply the issue isn't due to not finding an executable in the path. I suspect the issue is actually that we tried to invoke the compiler to query system includes and system defines, and that failed. Could you enable debug logging using: "C_Cpp.loggingLevel": "Debug", reload the window, and check the C/C++ output? There should be something there related to querying the compiler, including the command line we attempted to use to do so. Could you post that log output here?

[pelco]

Hi, Colen Garoutte-Carson (@Colengms) I didn't see any errors but maybe you can spot something.
cpp_debug.log

[pelco]

Colen Garoutte-Carson (@Colengms) There a error when querying the compiler:

Querying compiler for default C language standard using command line: "/home/pcoliveira/workspace/gateworks/openwrt/staging_dir/toolchain-arm_cortex-a9+neon_gcc-4.8-linaro_uClibc-0.9.33.2_eabi/bin//arm-openwrt-linux-gcc" -x c -E -dM /dev/null
terminating child process: 23541
Failed to query compiler at path "/home/pcoliveira/workspace/gateworks/openwrt/staging_dir/toolchain-arm_cortex-a9+neon_gcc-4.8-linaro_uClibc-0.9.33.2_eabi/bin//arm-openwrt-linux-gcc" for default standard versions.  Compiler querying is disabled for this compiler.
Querying compiler's default target using command line: "/home/pcoliveira/workspace/gateworks/openwrt/staging_dir/toolchain-arm_cortex-a9+neon_gcc-4.8-linaro_uClibc-0.9.33.2_eabi/bin//arm-openwrt-linux-gcc" -dumpmachine

[Colengms]

Hi Pedro Oliveira (@pelco) . I suspect arm-openwrt-linux-gcc has diverged from standard GCC and may not be reporting values/defines we depend on to detect its default C++ standard version. Can you provide the output of invoking the compiler with those args? ( -x c -E -dM /dev/null).

[pelco]

Hi Colen Garoutte-Carson (@Colengms) here it is. It seems to be working fine in cpptools v1.1.3.
arm-openwrt-linux-gcc.txt