read—write问题c++实现

#include <windows.h> #include <process.h> #include <iostream.h> //using namespace std; unsigned __stdcall reader1(PVOID pvParam); unsigned __stdcall reader2(PVOID pvParam); unsigned __stdcall writer1(PVOID pvParam); unsigned __stdcall writer2(PVOID pvParam); void write(); void read(); void realize_w(); void realized_r(); int Rcount=0; int Wcount=0; HANDLE Mut1; HANDLE Mut2; HANDLE Rmutex; HANDLE Wmutex; int main() { Mut1=::CreateSemaphore(NULL,1,1, NULL); Mut2=::CreateSemaphore(NULL,1,1, NULL); Rmutex=::CreateSemaphore(NULL,1,1, NULL); Wmutex=::CreateSemaphore(NULL,1,1, NULL); unsigned int threadid1; unsigned int threadid2; unsigned int threadid3; unsigned int threadid4; HANDLE hThread1; HANDLE hThread2; HANDLE hThread3; HANDLE hThread4; hThread1= (HANDLE)_beginthreadex(NULL,0,reader1,NULL,NULL,&threadid1); hThread2= (HANDLE)_beginthreadex(NULL,0,reader2,NULL,NULL,&threadid2); hThread3= (HANDLE)_beginthreadex(NULL,0,writer1,NULL,NULL,&threadid3); hThread4= (HANDLE)_beginthreadex(NULL,0,writer2,NULL,NULL,&threadid4); CloseHandle(hThread1); CloseHandle(hThread2); CloseHandle(hThread3); CloseHandle(hThread4); Sleep(20000); return 0; } unsigned __stdcall reader1(PVOID pvParam) { while(true) { //WaitForSingleObject(Mut1,INFINITE); //ReleaseSemaphore(Mut1,1,NULL); WaitForSingleObject(Mut2,INFINITE); Rcount=Rcount+1; if(Rcount==1) { WaitForSingleObject(Rmutex,INFINITE); } ReleaseSemaphore(Mut2,1,NULL); cout<<"&&&&&&&&&&&&&&"<<endl; //read(); cout<<"read A"<<endl; cout<<"read B"<<endl; cout<<"read C"<<endl; cout<<"read D"<<endl; WaitForSingleObject(Mut2,INFINITE); Rcount=Rcount-1; if(Rcount==0) { ReleaseSemaphore(Rmutex,1,NULL); } ReleaseSemaphore(Mut2,1,NULL); Sleep(1000); } return 0; } unsigned __stdcall reader2(PVOID pvParam) { while(true) { //WaitForSingleObject(Mut1,INFINITE); //ReleaseSemaphore(Mut1,1,NULL); WaitForSingleObject(Mut2,INFINITE); Rcount=Rcount+1; if(Rcount==1) { WaitForSingleObject(Rmutex,INFINITE); } ReleaseSemaphore(Mut2,1,NULL); cout<<"++++++++++++++++"<<endl; //read(); cout<<"read E"<<endl; cout<<"read F"<<endl; cout<<"read G"<<endl; cout<<"read H"<<endl; WaitForSingleObject(Mut2,INFINITE); Rcount=Rcount-1; if(Rcount==0) { ReleaseSemaphore(Rmutex,1,NULL); } ReleaseSemaphore(Mut2,1,NULL); Sleep(1000); } return 0; } unsigned __stdcall writer1(PVOID pvParam) { while(true) { WaitForSingleObject(Mut1,INFINITE); Wcount=Wcount+1; if(Wcount==1) { WaitForSingleObject(Rmutex,INFINITE); } ReleaseSemaphore(Mut1,1,NULL); WaitForSingleObject(Wmutex,INFINITE); //write(); cout<<"****************"<<endl; cout<<"the first write A"<<endl; cout<<"the second write B"<<endl; cout<<"the third write C"<<endl; cout<<"the forth write D"<<endl; WaitForSingleObject(Mut1,INFINITE); Wcount=Wcount-1; if(Wcount==0) { ReleaseSemaphore(Rmutex,1,NULL); } ReleaseSemaphore(Wmutex,1,NULL); ReleaseSemaphore(Mut1,1,NULL); Sleep(1000); } return 0; } unsigned __stdcall writer2(PVOID pvParam) { while(true) { WaitForSingleObject(Mut1,INFINITE); Wcount=Wcount+1; if(Wcount==1) { WaitForSingleObject(Rmutex,INFINITE); } ReleaseSemaphore(Mut1,1,NULL); WaitForSingleObject(Wmutex,INFINITE); //write(); cout<<"-------------------"<<endl; cout<<"the first write E"<<endl; cout<<"the second write F"<<endl; cout<<"the third write G"<<endl; cout<<"the forth write H"<<endl; WaitForSingleObject(Mut1,INFINITE); Wcount=Wcount-1; if(Wcount==0) { ReleaseSemaphore(Rmutex,1,NULL); } ReleaseSemaphore(Wmutex,1,NULL); ReleaseSemaphore(Mut1,1,NULL); // use_data_write(); Sleep(1000); } return 0; } /* void realized_r() { WaitForSingleObject(Mut1,INFINITE); ReleaseSemaphore(Mut1); WaitForSingleObject(Mut2,INFINITE); Rcount=Rcount+1; if(Rcount==1) WaitForSingleObject(Rmutex,INFINITE); ReleaseSemaphore(Mut2); cout<<"&&&&&&&&&&&&&&"<<endl; //read(); WaitForSingleObject(Mut2,INFINITE); Rcount=Rcount-1; if(Rcount==0) ReleaseSemaphore(Rmutex); ReleaseSemaphore(Mut2); } */ /*void realize_w() { WaitForSingleObject(Mut1,INFINITE); Wcount=Wcount+1; if(Wcount==1)WaitForSingleObject(Rmutex,INFINITE); ReleaseSemaphore(Mut1); WaitForSingleObject(Wmutex,INFINITE); //write(); cout<<"-------------------"<<endl; WaitForSingleObject(Mut1,INFINITE); Wcount=Wcount-1; if(Wcount==0)ReleaseSemaphore(Rmutex); ReleaseSemaphore(Wmutex); ReleaseSemaphore(Mut1); // use_data_write(); } */ void write() { cout<<"the first write A"<<endl; cout<<"the second write B"<<endl; cout<<"the third write C"<<endl; cout<<"the forth write D"<<endl; } void read() { cout<<"read A"<<endl; cout<<"read B"<<endl; cout<<"read C"<<endl; cout<<"read D"<<endl; } /* typedef int semaphore; semaphore Mut1=1; semaphore Mut2=1; semaphore Wmutex=1; semaphore Rmutex=1; int Rcount=0; int Wcount=0; void Writer() { down(Mut1); Wcount=Wcount+1; if(Wcount==1)down(Rmutex); up(Mut1); down(Wmutex); write(); down(Mut1); Wcount=Wcount-1; if(Wcount==0)up(Rmutex); up(Wmutex); up(Mut1); use_data_write();//非临界区 } void Rreder() { down(Mut1); up(Mut1); down(Mut2); Rcount=Rcount+1; if(Rcount==1) down(Rmutex); up(Mut2); read(); down(Mut2); Rcount=Rcount-1; if(Rcount==0) up(Rmutex); up(Mut2); } */