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I took a very simple Python C API example off the web. When I remove #include <iostream>, I can properly import it into Python. When I keep iostream in and try to import the DLL, Python gives me this error: ImportError: DLL load failed while importing fib: The specified module could not be found. I am using Python 3.10.

Note: the error is not because Python could not find fib.pyd or PyInit_fib

#include <Python.h>
#include <iostream>
int _fib(int n)
{
     //unimportant implementation details
     return 0;
}
static PyObject* fib(PyObject* self, PyObject* args)
{
    int n;
    return Py_BuildValue("i", _fib(n));
}
static PyMethodDef FibMethods[] = {
    {"fib", fib, METH_VARARGS, "Calculate the Fibonacci numbers (in C)."},
    {NULL, NULL, 0, NULL}  /* Sentinel */
};
static struct PyModuleDef ticlib={
    PyModuleDef_HEAD_INIT,
    "fib",
    "A fast tic tac toe implementation",
    -1,
    FibMethods,
    NULL,
    NULL,
    NULL,
    NULL

};

PyMODINIT_FUNC
PyInit_fib(void)
{
    using namespace std;
    return PyModule_Create(&ticlib);
}

It could possible be related to the dependencies of fib.pyd.

Broken version of fib.dll (includes iostream)

$ ldd fib.dll
        ntdll.dll => /cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll (0x7ffb9f9d0000)
        KERNEL32.DLL => /cygdrive/c/WINDOWS/System32/KERNEL32.DLL (0x7ffb9f1f0000)
        KERNELBASE.dll => /cygdrive/c/WINDOWS/System32/KERNELBASE.dll (0x7ffb9d1c0000)
        msvcrt.dll => /cygdrive/c/WINDOWS/System32/msvcrt.dll (0x7ffb9ed00000)
        libstdc++-6.dll => /cygdrive/c/Program Files (x86)/GtkSharp/2.12/bin/libstdc++-6.dll (0x6fc40000)
        python310.dll => /cygdrive/e/Python/Python310/python310.dll (0x7ffb2e400000)
        WS2_32.dll => /cygdrive/c/WINDOWS/System32/WS2_32.dll (0x7ffb9f0f0000)
        VERSION.dll => /cygdrive/c/WINDOWS/SYSTEM32/VERSION.dll (0x7ffb95e30000)
        RPCRT4.dll => /cygdrive/c/WINDOWS/System32/RPCRT4.dll (0x7ffb9f800000)
        libstdc++-6.dll => /cygdrive/e/msys64/mingw64/bin/libstdc++-6.dll (0x7ffb2de10000)
        ADVAPI32.dll => /cygdrive/c/WINDOWS/System32/ADVAPI32.dll (0x7ffb9db40000)
        sechost.dll => /cygdrive/c/WINDOWS/System32/sechost.dll (0x7ffb9f040000)
        ucrtbase.dll => /cygdrive/c/WINDOWS/System32/ucrtbase.dll (0x7ffb9d550000)
        VCRUNTIME140.dll => /cygdrive/c/WINDOWS/SYSTEM32/VCRUNTIME140.dll (0x7ffb84c50000)
        libgcc_s_seh-1.dll => /cygdrive/e/msys64/mingw64/bin/libgcc_s_seh-1.dll (0x7ffb98030000)
        libwinpthread-1.dll => /cygdrive/e/msys64/mingw64/bin/libwinpthread-1.dll (0x7ffb93370000)

Working version of fib.dll (does not include iostream)

$ ldd fib.dll
        ntdll.dll => /cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll (0x7ffb9f9d0000)
        KERNEL32.DLL => /cygdrive/c/WINDOWS/System32/KERNEL32.DLL (0x7ffb9f1f0000)
        KERNELBASE.dll => /cygdrive/c/WINDOWS/System32/KERNELBASE.dll (0x7ffb9d1c0000)
        msvcrt.dll => /cygdrive/c/WINDOWS/System32/msvcrt.dll (0x7ffb9ed00000)
        python310.dll => /cygdrive/e/Python/Python310/python310.dll (0x7ffb2e400000)
        WS2_32.dll => /cygdrive/c/WINDOWS/System32/WS2_32.dll (0x7ffb9f0f0000)
        RPCRT4.dll => /cygdrive/c/WINDOWS/System32/RPCRT4.dll (0x7ffb9f800000)
        VERSION.dll => /cygdrive/c/WINDOWS/SYSTEM32/VERSION.dll (0x7ffb95e30000)
        ADVAPI32.dll => /cygdrive/c/WINDOWS/System32/ADVAPI32.dll (0x7ffb9db40000)
        sechost.dll => /cygdrive/c/WINDOWS/System32/sechost.dll (0x7ffb9f040000)
        ucrtbase.dll => /cygdrive/c/WINDOWS/System32/ucrtbase.dll (0x7ffb9d550000)
        VCRUNTIME140.dll => /cygdrive/c/WINDOWS/SYSTEM32/VCRUNTIME140.dll (0x7ffb84c50000)
Julian LaGattuta
  • 11
  • 1
  • did you try `pip install iostream`. Assuming this is what you want, the link is here: https://pypi.org/project/iostream/ – D.L Jan 29 '23 at 22:28
  • You need to provide debugging details. On what environment do you run the python module? Did you check the PATH contains ```/cygdrive/e/msys64/mingw64/bin```(```E:\msys64\mingw64\bin```)? – relent95 Jan 30 '23 at 06:39

0 Answers0