[Python-Dev] Checking if unsigned int less then zero. (original) (raw)

Dmitriy Tochansky tochansky at tochlab.net
Fri Jun 22 10:09:54 CEST 2012

Hello! Playing with cpython source, I found some strange strings in socketmodule.c:

     if (flowinfo < 0 || flowinfo > 0xfffff) {
         PyErr_SetString(
             PyExc_OverflowError,
             "getsockaddrarg: flowinfo must be 0-1048575.");
         return 0;
     }
 if (flowinfo < 0 || flowinfo > 0xfffff) {
     PyErr_SetString(PyExc_OverflowError,
                     "getsockaddrarg: flowinfo must be 0-1048575.");
     return NULL;
 }

The flowinfo variable declared few strings above as unsgined int. Is there any practical sense in this check? Seems like gcc just removes this check. I think any compiler will generate code that checks as unsigned, for example in x86 its JAE/JGE. May be this code is for "bad" compilers or exotic arch?

-- Dmitriy

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