gcc -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations sys_mman/O_TRUNC.c -o sys_mman/O_TRUNC -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt -lxnet -lsocket -latomic
sys_mman/O_TRUNC.c:3:17: error: 'O_TRUNC' undeclared here (not in a function)
    3 | int const foo = O_TRUNC;
      |                 ^~~~~~~