// sysdep.h //	System-dependent interface.  Nachos uses the routines defined//	here, rather than directly calling the UNIX library functions, to//	simplify porting between versions of UNIX, and even to//	other systems, such as MSDOS and the Macintosh.//// Copyright (c) 1992-1993 The Regents of the University of California.// All rights reserved.  See copyright.h for copyright notice and limitation // of liability and disclaimer of warranty provisions.#ifndef SYSDEP_H#define SYSDEP_H#include "copyright.h"// Check file to see if there are any characters to be read.// If no characters in the file, return without waiting.extern bool PollFile(int fd);// File operations: open/read/write/lseek/close, and check for error// For simulating the disk and the console devices.extern int OpenForWrite(char *name);extern int OpenForReadWrite(char *name, bool crashOnError);extern void Read(int fd, char *buffer, int nBytes);extern int ReadPartial(int fd, char *buffer, int nBytes);extern void WriteFile(int fd, char *buffer, int nBytes);extern void Lseek(int fd, int offset, int whence);extern int Tell(int fd);extern void Close(int fd);extern bool Unlink(char *name);// Interprocess communication operations, for simulating the networkextern int OpenSocket();extern void CloseSocket(int sockID);extern void AssignNameToSocket(char *socketName, int sockID);extern void DeAssignNameToSocket(char *socketName);extern bool PollSocket(int sockID);extern void ReadFromSocket(int sockID, char *buffer, int packetSize);extern void SendToSocket(int sockID, char *buffer, int packetSize,char *toName);// Process control: abort, exit, and sleepextern void Abort();extern void Exit(int exitCode);extern void Delay(int seconds);// Initialize system so that cleanUp routine is called when user hits ctl-Cextern void CallOnUserAbort(VoidNoArgFunctionPtr cleanUp);// Initialize the pseudo random number generatorextern void RandomInit(unsigned seed);extern int Random();// Allocate, de-allocate an array, such that de-referencing// just beyond either end of the array will cause an errorextern char *AllocBoundedArray(int size);extern void DeallocBoundedArray(char *p, int size);// Other C library routines that are used by Nachos.// These are assumed to be portable, so we don't include a wrapper.extern "C" {int atoi(const char *str);double atof(const char *str);int abs(int i);#include <stdio.h>		// for printf, fprintf#include <string.h>		// for DEBUG, etc.}#endif // SYSDEP_H