Supporting search paths for headers and libraries

[Dariqq]

gcc and clang honor C_INLCUDE_PATH CPLUS_INCLUDE_PATH (OBJC_INCLUDE_PATH and OBJCPLUS_INCLUDE_PATH) environment variables to search for c,cxx, (objc, objcxx) headers.

Similarly LIBRARY_PATH can be used to specify a search path for libraries.

EDIT: For msvc appearently there are INLCUDE and LIB environment variables doing the same thing.

What problem will this solve?

A header that is in C_INCLUDE_PATH or a library in LIBRARY_PATH can be found by the compiler/linker.

os.findheader and os.findlib will currently fail to find them.

What might be a solution?

Extend os.findheader and os.findlib to recognise these values.

What other alternatives have you already considered?

Rather than searching through a list of search paths manually let the compiler/linker do it with small test programs.

Anything else we should know?
Add any other context or screenshots about the feature request here.

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[nickclark2016]

Are you asking to extend os.findheader and os.findlib to support those environment variables? If so, this can already be done:

os.findlib("mylib", { os.getenv('LIBRARY_PATH') })
os.findheader("myheader", { os.getenv('C_INCLUDE_PATH') })

[Dariqq]

Well yes, I could do that but i think it would be better to have it in the functions in premake.

The reason is that the while premake cannot find the header/library it is not a problem in practice as the c compiler will be . This could lead to an issue with generating wrong makefiles/etc assuming that a header/lib is not available when it in fact is.

I encountered this because it causes this failure in the tests when I ran them on a non fhs compliant linux system.

None of the directories that premake searches by default /lib64:/usr/lib64:/usr/local/lib64:/llib:/usr/lib:/usr/local/lib (and the include versions of these) exist and instead only the above environment variables are used to point the c compiler to the headers/libraries.

[==========] 2331 tests from 197 test suites ran. (1367 ms total)
[  PASSED  ] 2329 tests.
[  FAILED  ] 2 tests, listed below:
[  FAILED  ] base_os.findheader_stdheaders
...-premake-5.0.0-beta7.drv-0/source/tests/base/test_os.lua:92: expected true but was false
[  FAILED  ] base_os.findlib_FindSystemLib
...-premake-5.0.0-beta7.drv-0/source/tests/base/test_os.lua:68: expected true but was false