Documenting our reference count management

3 files changed, 44 insertions, 0 deletions

diff --git a/doc/Ensemble.3 b/doc/Ensemble.3
index febc48f..b768fd6 100644
--- a/doc/Ensemble.3
+++ b/doc/Ensemble.3
@@ -209,6 +209,27 @@ namespace whose list of exported commands is used if both the mapping
 dictionary and the subcommand list properties are NULL. May be read
 using \fBTcl_GetEnsembleNamespace\fR which returns a Tcl result code
 (\fBTCL_OK\fR, or \fBTCL_ERROR\fR if the token does not refer to an ensemble).
+.SH "REFERENCE COUNT MANAGEMENT"
+.PP
+\fBTcl_FindEnsemble\fR does not modify the reference count of its
+\fIcmdNameObj\fR argument; it only reads. Note however that this function may
+set the interpreter result; if that is the only place that is holding a
+reference to the object, it will be deleted.
+.PP
+The ensemble property getters (\fBTcl_GetEnsembleMappingDict\fR,
+\fBTcl_GetEnsembleParameterList\fR, \fBTcl_GetEnsembleSubcommandList\fR, and
+\fBTcl_GetEnsembleUnknownHandler\fR) do not manipulate the reference count of
+the values they provide out; if those are non-NULL, they will have a reference
+count of at least 1.  Note that these functions may set the interpreter
+result.
+.PP
+The ensemble property setters (\fBTcl_SetEnsembleMappingDict\fR,
+\fBTcl_SetEnsembleParameterList\fR, \fBTcl_SetEnsembleSubcommandList\fR, and
+\fBTcl_SetEnsembleUnknownHandler\fR) will increment the reference count of the
+new value of the property they are given if they succeed (and decrement the
+reference count of the old value of the property, if relevant). If the
+property setters return \fBTCL_ERROR\fR, the reference count of the Tcl_Obj
+argument is left unchanged.
 .SH "SEE ALSO"
 namespace(n), Tcl_DeleteCommandFromToken(3)
 .SH KEYWORDS
diff --git a/doc/Eval.3 b/doc/Eval.3
index 1abe6f2..2769595 100644
--- a/doc/Eval.3
+++ b/doc/Eval.3
@@ -207,6 +207,20 @@ the \fBreturn\fR, \fBbreak\fR, or \fBcontinue\fR command was
 invoked in an inappropriate place.
 This means that top-level applications should never see a return code
 from \fBTcl_EvalObjEx\fR other than \fBTCL_OK\fR or \fBTCL_ERROR\fR.
+.SH "REFERENCE COUNT MANAGEMENT"
+.PP
+\fBTcl_EvalObjEx\fR and \fBTcl_GlobalEvalObj\fR both increment and
+decrement the reference count of their \fIobjPtr\fR argument; you must
+not pass them any value with a reference count of zero. They also
+manipulate the interpreter result; you must not count on the
+interpreter result to hold the reference count of any value over
+these calls.
+.PP
+\fBTcl_EvalObjv\fR may increment and decrement the reference count of
+any value passed via its \fIobjv\fR argument; you must not pass any
+value with a reference count of zero. This function also manipulates
+the interpreter result; you must not count on the interpreter result
+to hold the reference count of any value over this call.
 
 .SH KEYWORDS
 execute, file, global, result, script, value
diff --git a/doc/ExprLongObj.3 b/doc/ExprLongObj.3
index 837e0a8..59413e1 100644
--- a/doc/ExprLongObj.3
+++ b/doc/ExprLongObj.3
@@ -98,6 +98,15 @@ containing the expression's value at \fI*resultPtrPtr\fR.
 In this case, the caller is responsible for calling
 \fBTcl_DecrRefCount\fR to decrement the value's reference count
 when it is finished with the value.
+.SH "REFERENCE COUNT MANAGEMENT"
+.PP
+\fBTcl_ExprLongObj\fR, \fBTcl_ExprDoubleObj\fR,
+\fBTcl_ExprBooleanObj\fR, and \fBTcl_ExprObj\fR all increment and
+decrement the reference count of their \fIobjPtr\fR arguments; you
+must not pass them any value with a reference count of zero. They also
+manipulate the interpreter result; you must not count on the
+interpreter result to hold the reference count of any value over these
+calls.
 
 .SH "SEE ALSO"
 Tcl_ExprLong, Tcl_ExprDouble, Tcl_ExprBoolean, Tcl_ExprString, Tcl_GetObjResult