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Blt_TreeCreate(3) BLT Library Procedures Blt_TreeCreate(3) ______________________________________________________________________________ NAME Blt_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 re- turns 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 ex- ist. 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 al- ready 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 ob- jects 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 in- terp->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 2.5 Blt_TreeCreate(3)
NAME | SYNOPSIS | ARGUMENTS | DESCRIPTION | RETURNS | EXAMPLE | KEYWORDS
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