get_system_attribute function seg default

[jennwuu]

int EXPORT_OUT_API SMO_getSystemAttribute(SMO_Handle p_handle, int periodIndex,
    SMO_systemAttribute attr, float **outValueArray, int *length)
//
//  Purpose: For the system at given time, get a particular attribute.
//
{
    int     errorcode = 0;
    float   temp;
    data_t *p_data;

    p_data = (data_t *)p_handle;

    if (p_data == NULL)
        errorcode = -1;
    else if (periodIndex < 0 || periodIndex >= p_data->Nperiods)
        errorcode = 422;
    else {
        // don't need to loop since there's only one system
        temp = getSystemValue(p_data, periodIndex, attr);

        *outValueArray = &temp;
        *length        = 1;
    }

    return set_error(p_data->error_handle, errorcode);
}

Reviewing this section of code from swmm solver, I think float temp should be float* temp instead because outValueArray is a double pointer.

@michaeltryby @cbuahin

This error is not caught because there isn't an unit test for get_system_attribute

[michaeltryby]

So this is actually a bug in the c library that causes Python to crash completely. Good catch!

[jennwuu]

yeah! I found it when i was extending output functionality in pyswmm

[cbuahin]

I will fix it in my PR.

[cbuahin]

Addressed through pyswmm/Stormwater-Management-Model#322