cc -pthread -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations pthread/pthread_getcpuclockid.c -o pthread/pthread_getcpuclockid -D_POSIX_C_SOURCE=202405L -lm -lpthread -liconv pthread/pthread_getcpuclockid.c:6:38: error: use of undeclared identifier 'pthread_getcpuclockid'; did you mean 'pthread_getspecific'? int (*foo)(pthread_t, clockid_t *) = pthread_getcpuclockid; ^~~~~~~~~~~~~~~~~~~~~ pthread_getspecific /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/pthread.h:367:17: note: 'pthread_getspecific' declared here void* _Nullable pthread_getspecific(pthread_key_t); ^ pthread/pthread_getcpuclockid.c:6:7: error: incompatible function pointer types initializing 'int (*)(pthread_t, clockid_t *)' (aka 'int (*)(struct _opaque_pthread_t *, clockid_t *)') with an expression of type 'void * _Nullable (pthread_key_t)' (aka 'void * _Nullable (unsigned long)') [-Werror,-Wincompatible-function-pointer-types] int (*foo)(pthread_t, clockid_t *) = pthread_getcpuclockid; ^ ~~~~~~~~~~~~~~~~~~~~~ 2 errors generated.