C++ ofstream寫入在Windows下不起作用。在Linux下工作正常

Question

以下代碼在Windows和GNU C++，VS10，VS12，Intel C++ 14.0下不起作用。下面的代碼可以在Linux和GNU C++ 4.7,4.8，Intel C++ 14，Open64 5.0下工作。在內部測試for-loop中用DIMEN-256替換DIMEN ...作品！？任何想法？

//============================// 
// Read and Write binary file // 
// using buffers    // 
//============================// 

#include <iostream> 
#include <fstream> 
#include <string> 
#include <cmath> 

using namespace std; 

int main() 
{ 
    // 1. variables and parameters 

    const long int DIMEN = static_cast<long int>(pow(10.0,8.0)); 
    const long int I_DO_MAX = 100; 
    const string fileName = "my_file.bin"; 
    ofstream fileOUT; 
    ifstream fileIN; 
    double* myArrayAlpha = new double [DIMEN]; 
    double* myArrayBeta = new double [DIMEN]; 
    long int i; 
    long int j; 

    // 2. build the array with some data 

    cout << " 1 --> Build the array with some data" << endl; 

    for (i = 0; i < DIMEN; i++) 
    { myArrayAlpha[i] = static_cast<double>(i); } 

    for (i = 0; i < I_DO_MAX; i++) 
    { 
    // 3. open the file stream 

    cout << "-------------->>> " << i << endl; 
    cout << " 2 --> Open the file stream" << endl; 

    fileOUT.open(fileName.c_str(), ios::out | ios::binary | ios::trunc); 
    fileIN.open(fileName.c_str(), ios::in | ios::binary); 

    // 4. test if the file stream is opened 

    cout << " 3 --> Test if the file stream is opened with success" << endl; 

    if (!fileOUT.is_open()) 
    { cout << "Error! The output file stream is not opened. Exit." 
      << endl; return -1; } 

    if (!fileIN.is_open()) 
    { cout << "Error! The input file stream is not opened. Exit." 
      << endl; return -1; } 

    // 5. write the contents of myArrayAlpha[] to a file 

    cout << " 4 --> Write and then Read to the file" << endl; 

    fileIN.seekg(0, fileIN.beg); 
    fileOUT.seekp(0); 

    fileOUT.write(reinterpret_cast<char*>(&myArrayAlpha[0]), 
        DIMEN * sizeof(double)); 
    fileIN.read(reinterpret_cast<char*>(&myArrayBeta[0]), 
       DIMEN * sizeof(double)); 

    // 6. test that I am writting and reading correctly 

    for (j = 0; j < DIMEN; j++) // replace DIMEN 
    {       // with DIMEN-256 to work under Windows 
     if (myArrayAlpha[j] != myArrayBeta[j]) 
     { cout << myArrayAlpha[j] << endl; 
     cout << myArrayBeta[j] << endl; 
     cout << "j = " << j << endl; 
     cout << "Error!"; return -1; } 
    } 

    cout << " 5 --> Read and Write with success" << endl; 
    cout << " 6 --> Close the I/O streams" << endl; 

    // 7. close the file stream 

    fileIN.close(); 
    fileOUT.close(); 
    } 

    // 8. free up the RAM 

    delete [] myArrayAlpha; 
    delete [] myArrayBeta; 

    return 0; 
} 

Answer 1

的問題是，你的數據沒有被刷新到write調用後外部序列，所以還是定位在內部緩衝區。在write()之後添加此行：

fileOUT << std::flush;