VC C++ 文件读写操作 Windows API

1、CreateFile
创建或打开、返回对象句柄

HANDLE CreateFile(
 LPCTSTR lpFileName,                                               // 指向文件名的指针 
 DWORD dwDesiredAccess,                                      // 访问模式（GENERIC_READ / GENERIC_WRITE） 
 DWORD dwShareMode,                                          // 共享模式 
 LPSECURITY_ATTRIBUTES lpSecurityAttributes,       // 指向安全属性的指针 
 DWORD dwCreationDisposition,                             // 如何创建 
 DWORD dwFlagsAndAttributes,                             // 文件属性 
 HANDLE hTemplateFile                                         // 用于复制文件句柄

); 
2、WriteFile   

BOOL WriteFile( 
  HANDLE hFile,                                            //文件句柄
  LPCVOID lpBuffer,                                     // 要写入的一个数据缓冲区 
  DWORD nNumberOfBytesToWrite,             //要写入数据的字节数量
  LPDWORD lpNumberOfBytesWritten,         // 实际写入文件的字节数量 
  LPOVERLAPPED lpOverlapped                   // OVERLAPPED结构体指针,
                                                             // 如果文件是以FILE_FLAG_OVERLAPPED方式打开的话,那么这个指针就不能为

NULL

);

3、ReadFile

BOOL ReadFile( 
  HANDLE hFile,                                 //文件的句柄
  LPVOID lpBuffer,                             // 用于保存读入数据的一个缓冲区
  DWORD nNumberOfBytesToRead,    //要读入的字符数

  LPDWORD lpNumberOfBytesRead,    //指向实际读取字节数的指针

  LPOVERLAPPED lpOverlapped          //OVERLAPPED结构体指针,
                                                     // 如果文件是以FILE_FLAG_OVERLAPPED方式打开的话,那么这个指针就不能为NULL

);

#include <windows.h>  
#include <cstdio>  
int main()  
{ 
    
    HANDLE hFile;  
    DWORD nBytes;  
    
    //写入文件  
    hFile = CreateFile(("test.out"),  
        GENERIC_WRITE,  
        FILE_SHARE_WRITE,  
        NULL,  
        CREATE_ALWAYS,  
        0,  
        NULL );  
    char msg[] = "Hello World!";  
    
    if( hFile != INVALID_HANDLE_VALUE )  
    {  
        WriteFile( hFile, msg, sizeof(msg)-1, &nBytes, NULL );  
        
        CloseHandle(hFile);  
    }  
    
    //读取文件  
    hFile = CreateFile(("test.out"),  
        GENERIC_READ,  
        FILE_SHARE_READ,  
        NULL,  
        OPEN_ALWAYS,  
        0,  
        NULL );  
    if( hFile != INVALID_HANDLE_VALUE )  
    {  
        char line[256]={0};  
        BOOL bResult;  
        bResult = ReadFile(hFile,   
            line,   
            sizeof(line),   
            &nBytes,   
            NULL) ;   
        
        if (nBytes != 0 )   
        {  
            printf("%s\r\n", line);  
        }  
        
        CloseHandle(hFile);  
        
    } 
    
}