I work on several projects that have initialization requirements that
need to grab control after Py_Initialize(), but before any user code
runs (via input, script, -c, etc...).
Note that these are Python clones that take advantage of an installed
python (using its $prefix/lib/pythonx.x/*.py and site-packages/*)
We could use
PyImport_AppendInittab("sitecustomize",initsitecustomize);
But if there already IS customization in sitecustomize.py, I've
blown it away (and have to look it up and force an import).
And if someone uses the -S flag, I'm screwed.
I propose a hook styled after Py_AtExit(func) called Py_AtInit(func)
which maintains a list of functions that are called in Py_Initialize
right after main and site initializations.
If the hook isn't used, then the cost is a single extra function
call at initialization. Here's a spurious example: A customer wants
a version of python that has all the math functions and his
extensions to act like builtins...
I would write (without refcnt or error checks ;-):
#include "Python.h"
static void after_init(void) {
PyObject *builtin,*builtin_dict,*math,*math_dict,*user,*user_dict;
builtin = PyImport_ImportModule("__builtin__");
builtin_dict = PyModule_GetDict(builtin);
math = PyImport_ImportModule("math");
math_dict = PyModule_GetDict(math);
user = PyImport_ImportModule("user");
user_dict = PyModule_GetDict(math);
PyDict_Update(builtin_dictionary, math_dict);
PyDict_Update(builtin_dictionary, user_dict);
}
int main(int argc, char** argv) {
PyImport_AppendInittab("user",inituser);
Py_AtInit(after_init);
return Py_Main(argc, argv);
}
voila! An extended Python with new builtins.
I actually want this to do some MPI initialization to setup a
single user prompt with broadcast which has to run after
Py_Initialize() but before the import of readline.
I've attached a copy of the patch (also going to patches
at sf.net)
Pat
--
Patrick Miller | (925) 423-0309 |
http://www.llnl.gov/CASC/people/pmiller
Son, when you grow up you will know who I really am.
I am just a child like you who has been forced to act
responsibly. -- Rod Byrnes
Index: dist/src/Include/pythonrun.h
===================================================================
RCS file: /cvsroot/python/python/dist/src/Include/pythonrun.h,v
retrieving revision 2.62
diff -c -r2.62 pythonrun.h
*** dist/src/Include/pythonrun.h 13 Feb 2003 22:07:52 -0000 2.62
--- dist/src/Include/pythonrun.h 30 Apr 2003 22:04:13 -0000
***************
*** 75,80 ****
--- 75,81 ----
PyAPI_FUNC(void) PyErr_Display(PyObject *, PyObject *, PyObject *);
PyAPI_FUNC(int) Py_AtExit(void (*func)(void));
+ PyAPI_FUNC(int) Py_AtInit(void (*func)(void));
PyAPI_FUNC(void) Py_Exit(int);
Index: dist/src/Python/pythonrun.c
===================================================================
RCS file: /cvsroot/python/python/dist/src/Python/pythonrun.c,v
retrieving revision 2.193
diff -c -r2.193 pythonrun.c
*** dist/src/Python/pythonrun.c 22 Apr 2003 11:18:00 -0000 2.193
--- dist/src/Python/pythonrun.c 30 Apr 2003 22:04:16 -0000
***************
*** 106,111 ****
--- 106,135 ----
return flag;
}
+ #define NINITFUNCS 32
+ static void (*initfuncs[NINITFUNCS])(void);
+ static int ninitfuncs = 0;
+
+ int Py_AtInit(void (*func)(void))
+ {
+ if (ninitfuncs >= NINITFUNCS)
+ return -1;
+ if (!func)
+ return -1;
+ initfuncs[ninitfuncs++] = func;
+ return 0;
+ }
+
+ static void initinitialize(void)
+ {
+ int i;
+ for(i=0;i