How can I run precompiled code objects?

howard at eegsoftware.com howard at eegsoftware.com
Fri Jul 13 20:29:47 CEST 2001


On Fri, 13 Jul 2001 13:20:57 +0200, "Alex Martelli"
<aleaxit at yahoo.com> wrote:

.....
>> Can anyone tell me how to use the so called "code objects" in Python, for
>> example the ones created via
>>
>> PyObject* Py_CompileString(char *str, char *filename, int start)
>>
........
>
>A "code block" is not suitable for eval(), so exec it will
>have to be, if you're working in Python as you said at the
>start.  If you're working in C as you say now, the C API
>function you have to call is PyEval_EvalCode.  It takes 3
>arguments -- a code object, then two dictionaries to use as
>local and global namespaces -- the last arg can be 0, but
>not the 2nd one.
>
.......
>
>Alex
>
>
>
So...I cut out the code sample (see below), located the extra includes
I needed (compile.h and eval.h) and tried it.

When I run my old method (PyRun_SimpleString), my script evaluates and
runs (Tkinter+PMW stuff) but I get an empty Tk window in addition to
my expected window.

When I run the PyEval_EvalCode method, it returns as though there was
not error but nothing (neither window) appears.  The result from
PyEval_EvalCode appears to be Py_None but is not null.

Any Ideas????

Here is the code sample (I had to read the file into memory because of
the (apparently) know PyRun_File bug).

int
pyrunfile(void)
{
    char *buf,*p;
    long size=0;
    int len,ans;
    FILE *fp;
    PyObject *ptype,*pvalue,*ptrace;

    fp=fopen("stages.py","r");
    if (fp)
        {
        buf=(char *)malloc(80000);
        if (!buf)
            return -1;
        p=buf;
        while (size < 80000 && !feof(fp))
            {
            p=fgets(p,1000,fp);
            if (!p)
                continue;
            len=strlen(p);
            size += len;
            p= &p[len];
            }
        fclose(fp);
#if 1
        ans=PyRun_SimpleString(buf);
        if (ans == -1)
            {
            PyErr_Fetch (&ptype, &pvalue, &ptrace);
            }
        free(buf);
        return 1;
#else
        PyObject *globals, *code, *result;

        /* prepare an innocuous 'globals' dictionary */
        globals = PyDict_New();
        PyDict_SetItemString(globals, "__builtins__",
                                 PyEval_GetBuiltins());

        /* compile your string of statements into a code object */
        code = Py_CompileString(buf, "stages.py", Py_file_input);
        if(!code) 
            {
            PyErr_Print();
            free(buf);
            return 0;
            }
        free(buf);

        /* execute the compiled statement */
        result = PyEval_EvalCode((PyCodeObject *)code, globals, 0);
        Py_DECREF(code);
        if(!result) 
            {
            PyErr_Print();
            return 0;
            } 
        else 
            {
            Py_DECREF(result);
            return 1;
            }
#endif
 }

Howard Lightstone
EEGSoftware
howard at eegsoftware.com



More information about the Python-list mailing list