__stdout_write.c\stdio\src - musl - musl - an implementation of the standard library for Linux-based systems

#include "stdio_impl.h"
#include <sys/ioctl.h>
size_t __stdout_write(FILE *f, const unsigned char *buf, size_t len)
{
	struct winsize wsz;
	f->write = __stdio_write;
	if (!(f->flags & F_SVB) && __syscall(SYS_ioctl, f->fd, TIOCGWINSZ, &wsz))
		f->lbf = -1;
	return __stdio_write(f, buf, len);
}