windows下利用文件映射實現(xiàn)共享內(nèi)存的辦法比較簡單，下面是實現(xiàn)代碼，細(xì)節(jié)用注釋說明．
調(diào)用類似linux下shm的操作．該類沒有進(jìn)行太多的測試，歡迎提出問題和bug～～：）
#include <windows.h>#include <string>#include <iostream>#include <assert.h>using std::string;using std::cout;using std::endl;#pragma warning(disable: 4311)class shareMemory{private: LPWSTR shm_name_u; bool is_create_file; void * sh_base; HANDLE semaphore; HANDLE file_mapping; int addr_len;public:/*create＿file用來說明是用磁盤文件映射還是頁文件映射，如果用磁盤文件映射，共享內(nèi)存不會出現(xiàn)存儲器release后出現(xiàn)違規(guī)訪問的問題，但是會在磁盤上建立一個文件，文件的名稱由參數(shù)shm＿name給定．如果用頁文件映射，則不會在磁盤上建立一個文件*/ shareMemory(const string& shm_name, bool create_file=false):is_create_file(create_file) {
const char * _c_shm_name = shm_name.c_str(); int _size =(int)shm_name.length()+1; shm_name_u=(LPWSTR)malloc(_size*2); MultiByteToWideChar(CP_ACP,0,_c_shm_name,_size,shm_name_u,_size); semaphore = CreateSemaphore(NULL,1,1,NULL); sh_base = NULL; file_mapping = INVALID_HANDLE_VALUE; } void * shm_open(void* addr,const int length, DWORD protect) { addr_len = length; HANDLE _file_handle = INVALID_HANDLE_VALUE; if(is_create_file) { _file_handle= CreateFile(shm_name_u,GENERIC_READ|GENERIC_WRITE,0, NULL,OPEN_ALWAYS,FILE_ATTRIBUTE_NORMAL,0);#ifdef _DEBUG if(_file_handle==INVALID_HANDLE_VALUE) cout<<"can not create file! we use page file instead!";#endif //end _DEBUG }/*打開指定名稱的文件映射，如果不存在則創(chuàng)建一個*/ file_mapping = OpenFileMapping(PAGE_READWRITE,false,shm_name_u ); if(file_mapping!=NULL) goto file_mapping_exist; file_mapping = CreateFileMapping(_file_handle,NULL,PAGE_READWRITE, 0,length,shm_name_u);#ifdef _DEBUG assert(file_mapping);#endif if(file_mapping==NULL) return NULL;file_mapping_exist: sh_base = MapViewOfFileEx(file_mapping,protect,0,0,length,addr); CloseHandle(_file_handle); return sh_base; }
/*往共享內(nèi)存中寫數(shù)據(jù)，返回寫出數(shù)據(jù)的字節(jié)個數(shù)*/ int shm_write(void *dest, void * src, int size) {
if(!check_adress(dest)) return -1; int _write_count = (int)sh_base+addr_len - (int)dest; if(_write_count>size) _write_count = size;/*利用semaphore進(jìn)行保護(hù)映射的區(qū)域（同一進(jìn)程的不同線程調(diào)用時候才進(jìn)行保護(hù)）*/ WaitForSingleObject(semaphore,INFINITE); memcpy(dest,src,_write_count); ReleaseSemaphore(semaphore,1,NULL); FlushViewOfFile(sh_base,_write_count); return _write_count; } /*從共享內(nèi)存中讀數(shù)據(jù)，返回讀出的數(shù)據(jù)字節(jié)個數(shù)＊*/int shm_read(void* src, void * dest, int size) { if(!check_adress(src)) return -1; int _read_count = (int)sh_base+addr_len -(int) src; if(_read_count>size) _read_count = size; memcpy(dest,src,_read_count); return _read_count; } ~shareMemory() { UnmapViewOfFile(sh_base); free(shm_name_u); CloseHandle(semaphore); CloseHandle(file_mapping); }private :/*進(jìn)行地址檢測*/ bool check_adress(void* addr) { if( ( (int)addr <(int)sh_base) || ((int)addr > (int)sh_base+addr_len) ) { SetLastError(ERROR_ACCESS_DENIED);#ifdef _DEBUG printf("access denied,the destination address out of the map view!");#endif //_DEBUG return false; } return true; }};
測試：
寫進(jìn)程的主函數(shù)：