posix-io/isatty.c

#include <windows.h>
#include <shared.h>
#include <errno.h>

int isatty(int fd) {
	BY_HANDLE_FILE_INFORMATION_NEW information;
	if(fd == -1) {
		errno = EBADF;
		return 0;
	}
	int r = !GetFileInformationByHandle((void *)fd, (BY_HANDLE_FILE_INFORMATION *)&information);
	if(r) {
		if(GetLastError() != ERROR_INVALID_FUNCTION) return 0;
		SetLastError(0);
	}
	return r;
}