Function npyiter_allocate_buffers

numpy/core/src/multiarray/nditer_api.c:1754–1804

* If errmsg is non-NULL, it should point to a variable which will * receive the error message, and no Python exception will be set. * This is so that the function can be called from code not holding * the GIL. */

 * the GIL.
 */
NPY_NO_EXPORT int
npyiter_allocate_buffers(NpyIter *iter, char **errmsg)
{
    /*npy_uint32 itflags = NIT_ITFLAGS(iter);*/
    /*int ndim = NIT_NDIM(iter);*/
    int iop = 0, nop = NIT_NOP(iter);

    npy_intp i;
    npyiter_opitflags *op_itflags = NIT_OPITFLAGS(iter);
    NpyIter_BufferData *bufferdata = NIT_BUFFERDATA(iter);
    PyArray_Descr **op_dtype = NIT_DTYPES(iter);
    npy_intp buffersize = NBF_BUFFERSIZE(bufferdata);
    char *buffer, **buffers = NBF_BUFFERS(bufferdata);

    for (iop = 0; iop < nop; ++iop) {
        npyiter_opitflags flags = op_itflags[iop];

        /*
         * If we have determined that a buffer may be needed,
         * allocate one.
         */
        if (!(flags&NPY_OP_ITFLAG_BUFNEVER)) {
            npy_intp itemsize = op_dtype[iop]->elsize;
            buffer = PyArray_malloc(itemsize*buffersize);
            if (buffer == NULL) {
                if (errmsg == NULL) {
                    PyErr_NoMemory();
                }
                else {
                    *errmsg = "out of memory";
                }
                goto fail;
            }
            if (PyDataType_FLAGCHK(op_dtype[iop], NPY_NEEDS_INIT)) {
                memset(buffer, '\0', itemsize*buffersize);
            }
            buffers[iop] = buffer;
        }
    }

    return 1;

fail:
    for (i = 0; i < iop; ++i) {
        if (buffers[i] != NULL) {
            PyArray_free(buffers[i]);
            buffers[i] = NULL;
        }
    }
    return 0;
}

/*
 * This sets the AXISDATA portion of the iterator to the specified