Linker Error with experimental::filesystem

When attempting to implement C 1z features using the experimental::filesystem library in GCC 6.0, users may encounter a linker error. The error message indicates an undefined reference to std::experimental::filesystem::v1::__cxx11::path::_M_split_cmpts().

Reason:

The Filesystem TS is not a part of C 1z but a separate specification. GCC's implementation of this library is available in C 11 mode.

Solution:

To resolve this issue, link with -lstdc fs. The libstdc fs.a library must come after objects that depend on it in the linker command.

Updates:

• November 2017: GCC 8.x implemented the C 17 Filesystem library in the std::filesystem namespace. This library can be used with -std=gnu 17 or -std=c 17 and still requires linking with -lstdc fs.
• January 2019: GCC 9 onwards allows the use of std::filesystem components without -lstdc fs.
• April 2024: GCC 13.3 added std::experimental::filesystem symbols to -lstdc exp.