/* unistd.h: POSIX constants and functions. */

#ifndef _UNISTD_H
#define _UNISTD_H

#define __need_NULL
#include <stddef.h>

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

#ifdef __cplusplus
extern "C"
{
#endif

    pid_t fork();

    /* Return the current process' process ID. */
    pid_t getpid(void);

    int execv(const char*, char* const*);
    int execve(const char*, char* const*, char* const*);
    int execvp(const char*, char* const*);

    /* Call the operating system kernel for a specific service. */
    long syscall(long num, ...);

    /* Sleep for X microseconds. */
    int usleep(useconds_t us);

    /* Sleep for X seconds. */
    unsigned long sleep(unsigned long seconds);

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

    /* Read bytes from a file descriptor. */
    ssize_t read(int fd, void* buf, size_t size);

#ifdef __cplusplus
}
#endif

#endif