[Cython] Cython code fails to compile with gcc 2.95

[Sven Berkvens-Matthijsse]

> Hi,
> 
> I know, that's a pretty old compiler, but I know someone with a Solaris
> production setup that still uses it. Here is the compile error he gets:
> 
> --------------------------------
> src/lxml/lxml.etree.c: In function `__pyx_PyInt_AsLongLong':
> src/lxml/lxml.etree.c:110165: parse error before `long'
> src/lxml/lxml.etree.c:110167: `val' undeclared (first use in this function)
> src/lxml/lxml.etree.c:110167: (Each undeclared identifier is reported only once
> src/lxml/lxml.etree.c:110167: for each function it appears in.)
> src/lxml/lxml.etree.c: In function `__pyx_PyInt_AsUnsignedLongLong':
> src/lxml/lxml.etree.c:110185: parse error before `long'
> src/lxml/lxml.etree.c:110187: `val' undeclared (first use in this function)
> error: command 'gcc' failed with exit status 1
> --------------------------------
> 
> The problem lies in the new type conversion functions:
> 
> --------------------------------
>  110156 static INLINE PY_LONG_LONG __pyx_PyInt_AsLongLong(PyObject* x) {
>  110157     if (PyInt_CheckExact(x)) {
>  110158         return PyInt_AS_LONG(x);
>  110159     }
>  110160     else if (PyLong_CheckExact(x)) {
>  110161         return PyLong_AsLongLong(x);
>  110162     }
>  110163     else {
>  110164         PyObject* tmp = PyNumber_Int(x); if (!tmp) return
> (PY_LONG_LONG)-1;
>  110165         PY_LONG_LONG val = __pyx_PyInt_AsLongLong(tmp);
>  110166         Py_DECREF(tmp);
>  110167         return val;
>  110168     }
>  110169 }
>  110170
>  110171 static INLINE unsigned PY_LONG_LONG
> __pyx_PyInt_AsUnsignedLongLong(PyObject* x) {
>  110172     if (PyInt_CheckExact(x)) {
>  110173         long val = PyInt_AS_LONG(x);
>  110174         if (unlikely(val < 0)) {
>  110175             PyErr_SetString(PyExc_TypeError, "Negative assignment to
> unsigned type.");
>  110176             return (unsigned PY_LONG_LONG)-1;
>  110177         }
>  110178         return val;
>  110179     }
>  110180     else if (PyLong_CheckExact(x)) {
>  110181         return PyLong_AsUnsignedLongLong(x);
>  110182     }
>  110183     else {
>  110184         PyObject* tmp = PyNumber_Int(x); if (!tmp) return
> (PY_LONG_LONG)-1;
>  110185         PY_LONG_LONG val = __pyx_PyInt_AsUnsignedLongLong(tmp);
>  110186         Py_DECREF(tmp);
>  110187         return val;
>  110188     }
>  110189 }
> --------------------------------
> 
> So it seems like this line doesn't compile:
> 
> --------------------------------
> PY_LONG_LONG val = __pyx_PyInt_AsLongLong(tmp);
> --------------------------------
> 
> Given the error, I would say that "PY_LONG_LONG" gets expanded to the usual
> "long long".
> 
> Any idea what could go wrong here and what to do about it?

The problem is that GCC 2.95 does not follow C99 semantics, and the C
version that it adheres to does not allow variables to be declared in
the middle of a block. All variables must be declared at the top of a
block. In the above case:

110164         PyObject* tmp = PyNumber_Int(x); if (!tmp) return (PY_LONG_LONG)-1;
110165         PY_LONG_LONG val = __pyx_PyInt_AsLongLong(tmp);

the 'if' statement on line 110164 terminates the end of the variable
declarations in the block. Line 110165 tries to declare one in the
middle of some statements, which was not allowed before C99.

> Stefan

-- 
Sven