Posts Tagged - mingw

Crossplatform C++ Arch detection

You can simply get current arch usign following code, where on windows can be used GetNativeSystemInfo() and on macos and linux uname() function:

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std::string GetOSArch()
{
#ifdef CPK_OS_WIN
    SYSTEM_INFO info;
    GetNativeSystemInfo(&info);
    switch (info.wProcessorArchitecture) {
        case PROCESSOR_ARCHITECTURE_AMD64:
            return "x86_64";
        case PROCESSOR_ARCHITECTURE_INTEL:
            return "x86";
        case PROCESSOR_ARCHITECTURE_IA64:
            return "ia64";
    };
#endif
#if defined(CPK_OS_LINUX) || defined(CPK_OS_MACOS)
    long ret = -1;
    struct utsname u;

    if (ret == -1)
        ret = uname(&u);
    if (ret != -1) {
        if (strlen(u.machine) == 4 && u.machine[0] == 'i'
                && u.machine[2] == '8' && u.machine[3] == '6')
            return std::string("x86");
        if (strcmp(u.machine, "amd64") == 0) // Solaris
            return std::string("x86_64");

        return std::string(u.machine);
    }
#endif
    return "";
}

OS detection can be done for example on cmake side or with other definition like __WIN32:

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if(WIN32)
    add_definitions(-DCPK_OS_WIN)
else()
    if (${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
        add_definitions(-DCPK_OS_MACOS)
    else()
        add_definitions(-DCPK_OS_LINUX)
    endif()
endif()

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Missmatch of libstd++ library / _zst28__throw_bad_array_new_lengthv error

For example you install new compiler or MinGW C++ and you met error of _zst28__throw_bad_array_new_lengthv after compile time. You can verify you compiler with simple example:

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#include <iostream>
#include <vector>

using namespace std;
int main(void)
{
    vector <int> a = {2, 0, 1}; // problem line
    cout << "hellow world";
    return 0;
}

If you still get error on such simple example you have system libstd++ missmatch. Your system is taking this library from some other part of the system (NOT from compiler directory) of the %PATH% location. Edit you PATH variable and make compiler directory (for example: c:\mingw64\bin) to be ABOVE the problematic one. Or with other words: compiler directory must have more priority. Very popular problematic place is git - C:\Git\mingw64\bin, move it to the end of %PATH%.

The error must go away.

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