gcc -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations unistd/posix_close.c -o unistd/posix_close -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt -lxnet -lsocket -latomic
unistd/posix_close.c:5:24: error: 'posix_close' undeclared here (not in a function)
    5 | int (*foo)(int, int) = posix_close;
      |                        ^~~~~~~~~~~