Backport version 1.21:

Document that the second argument to PyObject_IsInstance
may be a tuple. This closes SF patch
http://www.python.org/sf/649095

diff --git a/Doc/api/abstract.tex b/Doc/api/abstract.tex
index 5dcfd13335c52a24c4c303055f15175a673bd2bc..952b3d63a8a5333c802352a17a1759ecc5c85a62 100644 (file)
--- a/Doc/api/abstract.tex
+++ b/Doc/api/abstract.tex
@@ -171,15 +171,20 @@ for which they do not apply, they will raise a Python exception.
 \end{cfuncdesc}
 
 \begin{cfuncdesc}{int}{PyObject_IsInstance}{PyObject *inst, PyObject *cls}
-  Return \code{1} if \var{inst} is an instance of the class \var{cls}
-  or a subclass of \var{cls}.  If \var{cls} is a type object rather
-  than a class object, \cfunction{PyObject_IsInstance()} returns
-  \code{1} if \var{inst} is of type \var{cls}.  If \var{inst} is not a
-  class instance and \var{cls} is neither a type object or class
-  object, \var{inst} must have a \member{__class__} attribute --- the
-  class relationship of the value of that attribute with \var{cls}
-  will be used to determine the result of this function.
+  Returns \code{1} if \var{inst} is an instance of the class \var{cls}
+  or a subclass of \var{cls}, or \code{0} if not.  On error, returns
+  \code{-1} and sets an exception.  If \var{cls} is a type object
+  rather than a class object, \cfunction{PyObject_IsInstance()}
+  returns \code{1} if \var{inst} is of type \var{cls}.  If \var{cls}
+  is a tuple, the check will be done against every entry in \var{cls}.
+  The result will be \code{1} when at least one of the checks returns
+  \code{1}, otherwise it will be \code{0}. If \var{inst} is not a class
+  instance and \var{cls} is neither a type object, nor a class object,
+  nor a tuple, \var{inst} must have a \member{__class__} attribute
+  --- the class relationship of the value of that attribute with
+  \var{cls} will be used to determine the result of this function.
   \versionadded{2.1}
+  \versionchanged[Support for a tuple as the second argument added]{2.2}
 \end{cfuncdesc}
 
 Subclass determination is done in a fairly straightforward way, but