Documenting our reference count management

2 files changed, 41 insertions, 0 deletions

diff --git a/doc/Class.3 b/doc/Class.3
index 57203d5..5f8e061 100644
--- a/doc/Class.3
+++ b/doc/Class.3
@@ -241,6 +241,29 @@ NULL if the whole chain is to be processed (the argument itself is never
 NULL); this variable may be updated by the callback. The \fImethodNameObj\fR
 parameter gives an unshared object containing the name of the method being
 invoked, as provided by the user; this object may be updated by the callback.
+.SH "REFERENCE COUNT MANAGEMENT"
+.PP
+The \fIobjPtr\fR argument to \fBTcl_GetObjectFromObj\fR will not have its
+reference count manipulated, but this function may modify the interpreter
+result (to report any error) so interpreter results should not be fed into
+this without an additional reference being used.
+.PP
+The result of \fBTcl_GetObjectName\fR is a value that is owned by the object
+that is regenerated when this function is first called after the object is
+renamed.  If the value is to be retained at all, the caller should increment
+the reference count.
+.PP
+The first \fIobjc\fR values in the \fIobjv\fR argument to
+\fBTcl_NewObjectInstance\fR are the arguments to pass to the constructor. They
+must have a reference count of at least 1, and may have their reference counts
+changed during the running of the constructor. Constructors may modify the
+interpreter result, which consequently means that interpreter results should
+not be used as arguments without an additional reference being taken.
+.PP
+The \fImethodNameObj\fR argument to a Tcl_ObjectMapMethodNameProc
+implementation will be a value with a reference count of at least 1 where at
+least one reference is not held by the interpreter result. It is expected that
+method name mappers will only read their \fImethodNameObj\fR arguments.
 .SH "SEE ALSO"
 Method(3), oo::class(n), oo::copy(n), oo::define(n), oo::object(n)
 .SH KEYWORDS
diff --git a/doc/OpenFileChnl.3 b/doc/OpenFileChnl.3
index c1d1922..4e42b93 100644
--- a/doc/OpenFileChnl.3
+++ b/doc/OpenFileChnl.3
@@ -641,6 +641,24 @@ the channel was created with \fBTcl_OpenFileChannel\fR,
 \fBTcl_OpenCommandChannel\fR, or \fBTcl_MakeFileChannel\fR.  Other
 channel types may return a different type of handle on Windows
 platforms.
+.SH "REFERENCE COUNT MANAGEMENT"
+.PP
+The \fIreadObjPtr\fR argument to \fBTcl_ReadChars\fR must be an unshared
+value; it will be modified by this function.  Using the interpreter result for
+this purpose is \fIstrongly\fR not recommended; the preferred pattern is to
+use a new value from \fBTcl_NewObj\fR to receive the data and only to pass it
+to \fBTcl_SetObjResult\fR if this function succeeds.
+.PP
+The \fIlineObjPtr\fR argument to \fBTcl_GetsObj\fR must be an unshared value;
+it will be modified by this function.  Using the interpreter result for this
+purpose is \fIstrongly\fR not recommended; the preferred pattern is to use a
+new value from \fBTcl_NewObj\fR to receive the data and only to pass it to
+\fBTcl_SetObjResult\fR if this function succeeds.
+.PP
+The \fIwriteObjPtr\fR argument to \fBTcl_WriteObj\fR should be a value with
+any reference count. This function will not modify the reference count. Using
+the interpreter result without adding an additional reference to it is not
+recommended.
 .SH "SEE ALSO"
 DString(3), fconfigure(n), filename(n), fopen(3), Tcl_CreateChannel(3)
 .SH KEYWORDS