io.h\sys\include - musl - musl - an implementation of the standard library for Linux-based systems

#ifndef	_SYS_IO_H
#define	_SYS_IO_H
#ifdef __cplusplus
extern "C" {
#endif
#include <features.h>
#include <bits/io.h>
int iopl(int);
int ioperm(unsigned long, unsigned long, int);
#ifdef __cplusplus
}
#endif
#endif