From: Thomas Wouters <thomas@python.org>
Date: Thu, 2 Mar 2006 17:58:27 +0000 (+0000)
Subject: Explain why we use the unsigned int format for a signed int variable.
X-Git-Tag: v2.5a0~398
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=857b300b2e1c2b27af84d6090ed4810df00f1b16;p=thirdparty%2FPython%2Fcpython.git

Explain why we use the unsigned int format for a signed int variable.
(Should 'code' be cast to the right pointer type?)
---

diff --git a/Modules/fcntlmodule.c b/Modules/fcntlmodule.c
index d109e29e7c94..a368494c9696 100644
--- a/Modules/fcntlmodule.c
+++ b/Modules/fcntlmodule.c
@@ -96,6 +96,10 @@ static PyObject *
 fcntl_ioctl(PyObject *self, PyObject *args)
 {
 	int fd;
+	/* In PyArg_ParseTuple below, use the unsigned int 'I' format for
+	   the signed int 'code' variable, because Python turns 0x8000000
+	   into a large positive number (PyLong, or PyInt on 64-bit
+	   platforms,) whereas C expects it to be a negative int */
 	int code;
 	int arg;
 	int ret;