How to compile/ make this to be 64-bit

[quasi nexus]

// Function to save a vector of DataArray to a binary file
void saveDataToFile(const std::vector<KlineDataArray>& data, const std::string& filePath) 
{
    std::ofstream outFile(filePath, std::ios::binary);
    if (!outFile.is_open()) 
    {
        std::cerr << "Failed to open file for writing: " << filePath << '\n';
        return;
    }

    size_t dataSize{ data.size() };
    outFile.write(reinterpret_cast<const char*>(&dataSize), sizeof(size_t));
    outFile.write(reinterpret_cast<const char*>(data.data()), dataSize * sizeof(DataArray));

    //uint64_t dataSize = static_cast<uint64_t>(data.size());
    //outFile.write(reinterpret_cast<const char*>(&dataSize), sizeof(uint64_t));
    //outFile.write(reinterpret_cast<const char*>(data.data()), dataSize * sizeof(DataArray));
}

for some reason it still compiles / acts as a 32 bit instead of 64 bit. I do g++ -O3 -std=c++23 -m64 -o env environment.cpp and i have checked g++ -v
which ouptus:

Using built-in specs.
COLLECT_GCC=C:\msys64\ucrt64\bin\g++.exe
COLLECT_LTO_WRAPPER=C:/msys64/ucrt64/bin/../lib/gcc/x86_64-w64-mingw32/13.2.0/lto-wrapper.exe
Target: x86_64-w64-mingw32
Configured with: ../gcc-13.2.0/configure --prefix=/ucrt64 (and so on)

[pallid bone]

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[river topaz]

for some reason it still compiles / acts as a 32 bit
how do you know its acting 32 bit?

[quasi nexus]

because i have 14 files it works until the 12th file which is around 1,9gb big. The 13th file makes it 2.3gb but the program gets stuck at the .write() part when i do 13th files and between the both sizes is the signed 32-bit limit 2147... so i come to that conclusion

[river topaz]

well no that wouldnt be the problem anyway since size_t is unsigned so...

ah

wait no you're just unlucky here

I think write will max to 32 bit signed integer regardless

[quasi nexus]

bruh

[river topaz]

in some cases

[river topaz]

you can check the size of a pointer though to know if youre on 64 bit or 32

std::cout << CHAR_BIT * sizeof(void*);

should output 64 if youre on a 64 bit system and 32 if youre on 32

[river topaz]

the problem is write takes a streamsize which is implementation defined

if the implementors chose ptrdiff_t (which they might have as its used for signed size_t in other splace) then this could be restricted to 32 bit

[quasi nexus]

ye it outputs 64

[quasi nexus]

so nothing much i can do other then writing it in smaller chunks?

[river topaz]

yep

[river topaz]

especially on windows the underlying APIs use 32 bit integers for the size so its possible thats why its this way

[quasi nexus]

!solved