Compilation error: expected unqualified-id before numeric constant

[gav2xlin]

Ubuntu 25.04

~/coost$ cmake -B ./build -S . -- The C compiler identification is GNU 15.0.1 -- The CXX compiler identification is GNU 15.0.1 -- Detecting C compiler ABI info -- Detecting C compiler ABI info - done -- Check for working C compiler: /usr/bin/cc - skipped -- Detecting C compile features -- Detecting C compile features - done -- Detecting CXX compiler ABI info -- Detecting CXX compiler ABI info - done -- Check for working CXX compiler: /usr/bin/c++ - skipped -- Detecting CXX compile features -- Detecting CXX compile features - done -- The ASM compiler identification is GNU -- Found assembler: /usr/bin/cc -- Performing Test CMAKE_HAVE_LIBC_PTHREAD -- Performing Test CMAKE_HAVE_LIBC_PTHREAD - Success -- Found Threads: TRUE -- Configuring done (0.4s) -- Generating done (0.0s) -- Build files have been written to: /home/user/coost/build

$ cd build/ $ cmake --build . [ 2%] Building CXX object src/CMakeFiles/co.dir/base64.cc.o [ 5%] Building CXX object src/CMakeFiles/co.dir/benchmark.cc.o

/home/user/coost/include/co/time.h:41:17: error: expected unqualified-id before numeric constant 41 | extern xx::Unix unix; | ^~~~ gmake[2]: *** [src/CMakeFiles/co.dir/build.make:93: src/CMakeFiles/co.dir/benchmark.cc.o] Error 1 gmake[1]: *** [CMakeFiles/Makefile2:106: src/CMakeFiles/co.dir/all] Error 2 gmake: *** [Makefile:91: all] Error 2

I see in an IDE:

predefined macro unix 1

https://gcc.gnu.org/onlinedocs/cpp/System-specific-Predefined-Macros.html

extern xx::Mono mono; - a global variable extern xx::Unix unix; - a predefined macro