/usr/share/include-what-you-use/iwyu.gcc.imp is in iwyu 5.0-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 | # Default include mappings for IWYU with GCC
[
{ ref: gcc.libc.imp },
{ ref: gcc.symbols.imp },
{ ref: gcc.stl.headers.imp },
{ ref: stl.c.headers.imp },
{ ref: third_party.imp }
]
|