Blt_TreeCreate(3) BLT Library Procedures Blt_TreeCreate(3)______________________________________________________________________________NAMEBlt_TreeCreate - Create tree data object.
SYNOPSIS
#include <bltTree.h>
int
Blt_TreeCreate(interp, name, tokenPtr)
ARGUMENTS
Tcl_Interp *interp (in) Interpreter to report results back to.
const char *name (in) Name of the new tree. Can be quali‐
fied by a namespace.
Blt_Tree *tokenPtr (out) If not NULL, points to location to
store the client tree token.
_________________________________________________________________DESCRIPTION
This procedure creates a C-based tree data object and optionally
returns a token to it. The arguments are as follows:
interp Interpreter to report results back to. If an error occurs,
then interp->result will contain an error message.
name Name of the new tree object. You can think of name as the
memory address of the object. It's a unique name that iden‐
tifies the tree object. No tree object name can already
exist. Name can be qualified by a namespace such as
fred::myTree. If no namespace qualifier is used, the tree
will be created in the current namespace, not the global
namespace. If a qualifier is present, the namespace must
already exist.
tokenPtr Holds the returned token. TokenPtr points to a location
where it is stored. Tree tokens are used to work with the
tree object. If NULL, no token is allocated. You can later
use Tcl_TreeGetToken to obtain a token.
The new tree data object created will initially contain only a root
node. You can add new nodes with Blt_TreeCreateNode.
Optionally a token for the tree data object is returned. Tree data
objects can be shared. For example, the tree and hiertable commands
may be accessing the same tree data object. Each client grabs a token
that is associated with the tree. When all tokens are released (see
Blt_TreeReleaseToken) the tree data object is automatically destroyed.
RETURNS
A standard Tcl result is returned. If TCL_ERROR is returned, then
interp->result will contain an error message. The following errors may
occur:
· There already exists a tree by the same name as name. You can use
Tcl_TreeExists to determine if a tree exists beforehand.
· The tree name is prefixed by a namespace that doesn't exist. If you
qualified the tree name with a namespace, the namespace must exist.
Unlike Tcl procs and variables, the namespace is not automatically
created for you.
· Memory can't be allocated for the tree or token.
EXAMPLE
The following example creates a new
Blt_Tree token;
if (Blt_TreeCreate(interp, "myTree", &token) != TCL_OK) {
return TCL_ERROR;
}
printf("tree is %s\n", Blt_TreeName(token));
KEYWORDS
Tcl_TreeGetToken, Tcl_TreeExists, Tcl_TreeReleaseToken
BLT 2.4 Blt_TreeCreate(3)
