#ifndef __UNISTD_H__
# define __UNISTD_H__

#ifdef __cplusplus
extern "C" {
#endif

#include <stdio.h>
#include <stdint.h>
#include <sys/types.h>

/* Standard file descriptors. */
#define STDIN_FILENO    0
#define STDOUT_FILENO   1
#define STDERR_FILENO   2

/* Write data to a file descriptor; returns number of bytes written or -1. */
extern ssize_t write(int __fd, const void *__buf, size_t __nbytes);

/* Read data from a file descriptor; returns number of bytes read or -1. */
extern ssize_t read(int __fd, void *__buf, size_t __nbytes);

/* Read at a specific position from a file descriptor. */
extern ssize_t pread(int __fd, void *__buf, size_t __nbytes, off_t __offset);

/* Write at a specific position to a file descriptor. */
extern ssize_t pwrite(int __fd, const void *__buf, size_t __n, off_t __offset);

/* Seek at an offset from SEEK_SET/SEEK_CUR/SEEK_END; returns new position. */
extern off_t lseek(int __fd, off_t __offset, int __whence);

/* Close a file descriptor. */
extern int close(int __fd);

/* Remove a file. */
extern int unlink(const char *__path);

/* Create a directory. */
extern int mkdir(const char *__path, mode_t __mode);

/* Remove an empty directory. */
extern int rmdir(const char *__path);

extern char *getcwd(char *__buf, size_t __size);

extern int chdir(char const *__path);

extern int isatty(int __fd);

extern int dup(int __fd);

/* Exit immediately, bypassing exit handlers or signal handlers. */
__attribute__((noreturn))
extern void _exit(int __status);


/* Kernel-style functions supported only by Vhex. */

//---
// Process part
///---
/* Get the process ID of the calling process. */
extern pid_t getpid(void);

/* Get the process group ID of the calling process. */
extern pid_t getpgid(void);

/* Get the process ID of the calling process's parent. */
extern pid_t getppid(void);

/*
** Set the process group ID of the process matching PID to PGID.
** If PID is zero, the current process's process group ID is set.
** If PGID is zero, the process ID of the process is used.
*/
extern int setpgid(pid_t __pid, pid_t __pgid);

//---
// System part
//---
/*
** Get the `_PC_*' symbols for the NAME argument to `pathconf' and `fpathconf';
** the `_SC_*' symbols for the NAME argument to `sysconf'; and the `_CS_*'
** symbols for the NAME argument to `confstr'.
*/
#include <bits/confname.h>

/* Get the value of the system variable NAME. */
extern long int sysconf(int __name);

#ifdef __cplusplus
}
#endif

#endif /*__UNISTD_H__*/