rb_reserved_fd_p 64 ext/socket/init.c if (!is_socket(fd) || rb_reserved_fd_p(fd)) { rb_reserved_fd_p 561 include/ruby/intern.h int rb_reserved_fd_p(int fd); rb_reserved_fd_p 567 include/ruby/intern.h #define RB_RESERVED_FD_P(fd) rb_reserved_fd_p(fd) rb_reserved_fd_p 7612 io.c if (rb_reserved_fd_p(fd)) { rb_reserved_fd_p 297 process.c if (rb_reserved_fd_p(fd)) { /* async-signal-safe */