Function npyiter_clear_buffers

numpy/core/src/multiarray/nditer_api.c:2609–2654

* This function clears any references still held by the buffers and should * only be used to discard buffers if an error occurred. * * @param iter Iterator */

 * @param iter Iterator
 */
NPY_NO_EXPORT void
npyiter_clear_buffers(NpyIter *iter)
{
    int nop = iter->nop;
    NpyIter_BufferData *bufferdata = NIT_BUFFERDATA(iter);

    if (NBF_SIZE(bufferdata) == 0) {
        /* if the buffers are empty already, there is nothing to do */
        return;
    }

    /*
     * The iterator may be using a dtype with references (as of writing this
     * means Python objects, but does not need to stay that way).
     * In that case, further cleanup may be necessary and we clear buffers
     * explicitly.
     */
    PyObject *type, *value, *traceback;
    PyErr_Fetch(&type,  &value, &traceback);

    /* Cleanup any buffers with references */
    char **buffers = NBF_BUFFERS(bufferdata);

    NpyIter_TransferInfo *transferinfo = NBF_TRANSFERINFO(bufferdata);
    PyArray_Descr **dtypes = NIT_DTYPES(iter);
    npyiter_opitflags *op_itflags = NIT_OPITFLAGS(iter);
    for (int iop = 0; iop < nop; ++iop, ++buffers) {
        if (transferinfo[iop].clear.func == NULL ||
                 !(op_itflags[iop]&NPY_OP_ITFLAG_USINGBUFFER)) {
            continue;
        }
        if (*buffers == 0) {
            continue;
        }
        int itemsize = dtypes[iop]->elsize;
        if (transferinfo[iop].clear.func(NULL,
                dtypes[iop], *buffers, NBF_SIZE(bufferdata), itemsize,
                transferinfo[iop].clear.auxdata) < 0) {
            /* This should never fail; if it does write it out */
            PyErr_WriteUnraisable(NULL);
        }
    }
    /* Signal that the buffers are empty */
    NBF_SIZE(bufferdata) = 0;
    PyErr_Restore(type, value, traceback);
}


/*