cc -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations sys_socket/accept4.c -o sys_socket/accept4 -D_POSIX_C_SOURCE=202405L  -lm -lpthread  -liconv
sys_socket/accept4.c:5:72: error: use of undeclared identifier 'accept4'; did you mean 'accept'?
int (*foo)(int, struct sockaddr *restrict, socklen_t *restrict, int) = accept4;
                                                                       ^~~~~~~
                                                                       accept
/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/sys/socket.h:724:9: note: 'accept' declared here
int     accept(int, struct sockaddr * __restrict, socklen_t * __restrict)
        ^
sys_socket/accept4.c:5:7: error: incompatible function pointer types initializing 'int (*)(int, struct sockaddr *restrict, socklen_t *restrict, int)' (aka 'int (*)(int, struct sockaddr *restrict, unsigned int *restrict, int)') with an expression of type 'int (int, struct sockaddr *restrict, socklen_t *restrict)' (aka 'int (int, struct sockaddr *restrict, unsigned int *restrict)') [-Werror,-Wincompatible-function-pointer-types]
int (*foo)(int, struct sockaddr *restrict, socklen_t *restrict, int) = accept4;
      ^                                                                ~~~~~~~
2 errors generated.