Skip to content

gh-148675: Use a string for ctypes cparam tag #149778

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
vstinner wants to merge 2 commits into
base: main
Choose a base branch
from
+50 −39
Open

gh-148675: Use a string for ctypes cparam tag #149778

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
f40bea4
gh-148675: Use a string for ctypes cparam tag
vstinner May 13, 2026
85808d5
Fix PyCArg_repr() for "q" and "Q" formats
vstinner May 13, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
8 changes: 8 additions & 0 deletions Lib/test/test_ctypes/test_parameters.py
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
import sys
import unittest
import test.support
import ctypes
from ctypes import (CDLL, PyDLL, ArgumentError,
Structure, Array, Union,
_Pointer, _SimpleCData, _CFuncPtr,
Expand Down Expand Up @@ -247,6 +248,13 @@ def test_parameter_repr(self):
self.assertRegex(repr(c_char_p.from_param(b'hihi')), r"^<cparam 'z' \(0x[A-Fa-f0-9]+\)>$")
self.assertRegex(repr(c_wchar_p.from_param('hihi')), r"^<cparam 'Z' \(0x[A-Fa-f0-9]+\)>$")
self.assertRegex(repr(c_void_p.from_param(0x12)), r"^<cparam 'P' \(0x0*12\)>$")
if hasattr(ctypes, 'c_double_complex'):
self.assertRegex(repr(ctypes.c_double_complex.from_param(0)),
r"^<cparam 'Zd' at 0x[A-Fa-f0-9]+>$")
self.assertRegex(repr(ctypes.c_float_complex.from_param(0)),
r"^<cparam 'Zf' at 0x[A-Fa-f0-9]+>$")
self.assertRegex(repr(ctypes.c_longdouble_complex.from_param(0)),
r"^<cparam 'Zg' at 0x[A-Fa-f0-9]+>$")

@test.support.cpython_only
def test_from_param_result_refcount(self):
Expand Down
32 changes: 17 additions & 15 deletions Modules/_ctypes/_ctypes.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -708,7 +708,7 @@ StructUnionType_paramfunc(ctypes_state *st, CDataObject *self)
}
assert(stginfo); /* Cannot be NULL for structure/union instances */

parg->tag = 'V';
parg->tag = "V";
parg->pffi_type = &stginfo->ffi_type_pointer;
parg->value.p = ptr;
parg->size = self->b_size;
Expand Down Expand Up @@ -1282,7 +1282,7 @@ PyCPointerType_paramfunc(ctypes_state *st, CDataObject *self)
if (parg == NULL)
return NULL;

parg->tag = 'P';
parg->tag = "P";
parg->pffi_type = &ffi_type_pointer;
parg->obj = Py_NewRef(self);
parg->value.p = *(void **)self->b_ptr;
Expand Down Expand Up @@ -1703,7 +1703,7 @@ PyCArrayType_paramfunc(ctypes_state *st, CDataObject *self)
PyCArgObject *p = PyCArgObject_new(st);
if (p == NULL)
return NULL;
p->tag = 'P';
p->tag = "P";
p->pffi_type = &ffi_type_pointer;
p->value.p = (char *)self->b_ptr;
p->obj = Py_NewRef(self);
Expand Down Expand Up @@ -1909,7 +1909,7 @@ c_wchar_p_from_param_impl(PyObject *type, PyTypeObject *cls, PyObject *value)
if (parg == NULL)
return NULL;
parg->pffi_type = &ffi_type_pointer;
parg->tag = 'Z';
parg->tag = "Z";
parg->obj = fd->setfunc(&parg->value, value, 0);
if (parg->obj == NULL) {
Py_DECREF(parg);
Expand Down Expand Up @@ -1998,7 +1998,7 @@ c_char_p_from_param_impl(PyObject *type, PyTypeObject *cls, PyObject *value)
if (parg == NULL)
return NULL;
parg->pffi_type = &ffi_type_pointer;
parg->tag = 'z';
parg->tag = "z";
parg->obj = fd->setfunc(&parg->value, value, 0);
if (parg->obj == NULL) {
Py_DECREF(parg);
Expand Down Expand Up @@ -2092,7 +2092,7 @@ c_void_p_from_param_impl(PyObject *type, PyTypeObject *cls, PyObject *value)
if (parg == NULL)
return NULL;
parg->pffi_type = &ffi_type_pointer;
parg->tag = 'P';
parg->tag = "P";
parg->obj = fd->setfunc(&parg->value, value, sizeof(void*));
if (parg->obj == NULL) {
Py_DECREF(parg);
Expand All @@ -2110,7 +2110,7 @@ c_void_p_from_param_impl(PyObject *type, PyTypeObject *cls, PyObject *value)
if (parg == NULL)
return NULL;
parg->pffi_type = &ffi_type_pointer;
parg->tag = 'z';
parg->tag = "z";
parg->obj = fd->setfunc(&parg->value, value, 0);
if (parg->obj == NULL) {
Py_DECREF(parg);
Expand All @@ -2127,7 +2127,7 @@ c_void_p_from_param_impl(PyObject *type, PyTypeObject *cls, PyObject *value)
if (parg == NULL)
return NULL;
parg->pffi_type = &ffi_type_pointer;
parg->tag = 'Z';
parg->tag = "Z";
parg->obj = fd->setfunc(&parg->value, value, 0);
if (parg->obj == NULL) {
Py_DECREF(parg);
Expand All @@ -2152,7 +2152,7 @@ c_void_p_from_param_impl(PyObject *type, PyTypeObject *cls, PyObject *value)
if (PyCArg_CheckExact(st, value)) {
/* byref(c_xxx()) */
PyCArgObject *a = (PyCArgObject *)value;
if (a->tag == 'P') {
if (strcmp(a->tag, "P") == 0) {
return Py_NewRef(value);
}
}
Expand All @@ -2165,7 +2165,7 @@ c_void_p_from_param_impl(PyObject *type, PyTypeObject *cls, PyObject *value)
if (parg == NULL)
return NULL;
parg->pffi_type = &ffi_type_pointer;
parg->tag = 'P';
parg->tag = "P";
Py_INCREF(value);
// Function pointers don't change their contents, no need to lock
parg->value.p = *(void **)func->b_ptr;
Expand All @@ -2191,7 +2191,7 @@ c_void_p_from_param_impl(PyObject *type, PyTypeObject *cls, PyObject *value)
if (parg == NULL)
return NULL;
parg->pffi_type = &ffi_type_pointer;
parg->tag = 'Z';
parg->tag = "Z";
parg->obj = Py_NewRef(value);
/* Remember: b_ptr points to where the pointer is stored! */
Py_BEGIN_CRITICAL_SECTION(value);
Expand Down Expand Up @@ -2332,7 +2332,8 @@ PyCSimpleType_paramfunc(ctypes_state *st, CDataObject *self)
if (parg == NULL)
return NULL;

parg->tag = fmt[0];
assert(strcmp(fd->code, fmt) == 0);
parg->tag = fd->code;
parg->pffi_type = fd->pffi_type;
parg->obj = Py_NewRef(self);
memcpy(&parg->value, self->b_ptr, self->b_size);
Expand Down Expand Up @@ -2578,7 +2579,8 @@ PyCSimpleType_from_param_impl(PyObject *type, PyTypeObject *cls,
if (parg == NULL)
return NULL;

parg->tag = fmt[0];
assert(strcmp(fd->code, fmt) == 0);
parg->tag = fd->code;
parg->pffi_type = fd->pffi_type;
parg->obj = fd->setfunc(&parg->value, value, info->size);
if (parg->obj)
Expand Down Expand Up @@ -2832,7 +2834,7 @@ PyCFuncPtrType_paramfunc(ctypes_state *st, CDataObject *self)
if (parg == NULL)
return NULL;

parg->tag = 'P';
parg->tag = "P";
parg->pffi_type = &ffi_type_pointer;
parg->obj = Py_NewRef(self);
parg->value.p = *(void **)self->b_ptr;
Expand Down Expand Up @@ -4303,7 +4305,7 @@ _byref(ctypes_state *st, PyObject *obj)
return NULL;
}

parg->tag = 'P';
parg->tag = "P";
parg->pffi_type = &ffi_type_pointer;
parg->obj = obj;
parg->value.p = ((CDataObject *)obj)->b_ptr;
Expand Down
45 changes: 23 additions & 22 deletions Modules/_ctypes/callproc.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -468,7 +468,7 @@ PyCArgObject_new(ctypes_state *st)
if (p == NULL)
return NULL;
p->pffi_type = NULL;
p->tag = '\0';
p->tag = "";
p->obj = NULL;
memset(&p->value, 0, sizeof(p->value));
PyObject_GC_Track(p);
Expand Down Expand Up @@ -512,45 +512,50 @@ static PyObject *
PyCArg_repr(PyObject *op)
{
PyCArgObject *self = _PyCArgObject_CAST(op);
switch(self->tag) {

if (strlen(self->tag) != 1) {
goto generic;
}

switch(self->tag[0]) {
case 'b':
case 'B':
return PyUnicode_FromFormat("<cparam '%c' (%d)>",
return PyUnicode_FromFormat("<cparam '%s' (%d)>",
self->tag, self->value.b);
case 'h':
case 'H':
return PyUnicode_FromFormat("<cparam '%c' (%d)>",
return PyUnicode_FromFormat("<cparam '%s' (%d)>",
self->tag, self->value.h);
case 'i':
case 'I':
return PyUnicode_FromFormat("<cparam '%c' (%d)>",
return PyUnicode_FromFormat("<cparam '%s' (%d)>",
self->tag, self->value.i);
case 'l':
case 'L':
return PyUnicode_FromFormat("<cparam '%c' (%ld)>",
return PyUnicode_FromFormat("<cparam '%s' (%ld)>",
self->tag, self->value.l);

case 'q':
case 'Q':
return PyUnicode_FromFormat("<cparam '%c' (%lld)>",
return PyUnicode_FromFormat("<cparam '%s' (%lld)>",
self->tag, self->value.q);
case 'd':
case 'f': {
PyObject *f = PyFloat_FromDouble((self->tag == 'f') ? self->value.f : self->value.d);
PyObject *f = PyFloat_FromDouble((strcmp(self->tag, "f") == 0) ? self->value.f : self->value.d);
if (f == NULL) {
return NULL;
}
PyObject *result = PyUnicode_FromFormat("<cparam '%c' (%R)>", self->tag, f);
PyObject *result = PyUnicode_FromFormat("<cparam '%s' (%R)>", self->tag, f);
Py_DECREF(f);
return result;
}
case 'c':
if (is_literal_char((unsigned char)self->value.c)) {
return PyUnicode_FromFormat("<cparam '%c' ('%c')>",
return PyUnicode_FromFormat("<cparam '%s' ('%c')>",
self->tag, self->value.c);
}
else {
return PyUnicode_FromFormat("<cparam '%c' ('\\x%02x')>",
return PyUnicode_FromFormat("<cparam '%s' ('\\x%02x')>",
self->tag, (unsigned char)self->value.c);
}

Expand All @@ -561,20 +566,16 @@ PyCArg_repr(PyObject *op)
case 'z':
case 'Z':
case 'P':
return PyUnicode_FromFormat("<cparam '%c' (%p)>",
return PyUnicode_FromFormat("<cparam '%s' (%p)>",
self->tag, self->value.p);
break;

default:
if (is_literal_char((unsigned char)self->tag)) {
return PyUnicode_FromFormat("<cparam '%c' at %p>",
(unsigned char)self->tag, (void *)self);
}
else {
return PyUnicode_FromFormat("<cparam 0x%02x at %p>",
(unsigned char)self->tag, (void *)self);
}
break;
}

generic:
return PyUnicode_FromFormat("<cparam '%s' at %p>",
self->tag, (void *)self);
}

static PyMemberDef PyCArgType_members[] = {
Expand Down Expand Up @@ -1807,7 +1808,7 @@ _ctypes_byref_impl(PyObject *module, PyObject *obj, Py_ssize_t offset)
if (parg == NULL)
return NULL;

parg->tag = 'P';
parg->tag = "P";
parg->pffi_type = &ffi_type_pointer;
parg->obj = Py_NewRef(obj);
parg->value.p = (char *)((CDataObject *)obj)->b_ptr + offset;
Expand Down
4 changes: 2 additions & 2 deletions Modules/_ctypes/ctypes.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -494,7 +494,7 @@ PyObject *_ctypes_callproc(ctypes_state *st,
struct tagPyCArgObject {
PyObject_HEAD
ffi_type *pffi_type;
char tag;
const char *tag;
union {
char c;
char b;
Expand All @@ -511,7 +511,7 @@ struct tagPyCArgObject {
long double G[2];
} value;
PyObject *obj;
Py_ssize_t size; /* for the 'V' tag */
Py_ssize_t size; /* for the "V" tag */
};

#define _PyCArgObject_CAST(op) ((PyCArgObject *)(op))
Expand Down
Loading