musl/include/errno.h

#ifndef	_ERRNO_H
#define _ERRNO_H

#ifdef __cplusplus
extern "C" {
#endif

#include <bits/errno.h>

#ifdef __GNUC__
__attribute__((const))
#endif
extern int *__errno_location(void);
#define errno (*__errno_location())

#ifdef __cplusplus
}
#endif

#endif
initial check-in, version 0.5.0 15 years ago			`#ifndef _ERRNO_H`
			`#define _ERRNO_H`

			`#ifdef __cplusplus`
			`extern "C" {`
			`#endif`

			`#include <bits/errno.h>`

use __attribute__((const)) for errno and pthread_self if __GNUC__ is defined this is not too ugly and should result in significant code size and performance improvements for many programs. 15 years ago			`#ifdef __GNUC__`
			`__attribute__((const))`
			`#endif`
initial check-in, version 0.5.0 15 years ago			`extern int *__errno_location(void);`
			`#define errno (*__errno_location())`

			`#ifdef __cplusplus`
			`}`
			`#endif`

			`#endif`