Blt_TreeExists(3)

💖 Blt_TreeExists(3) 💖

okay bestie, so this one is from the BLT Library Procedures era, and it's genuinely one of the chillest little functions in the whole tree situation. no cap. it just tells you if a thing exists. that's it. that's the whole vibe. ✨

🌸 NAME 🌸

Blt_TreeExists — literally just "hey does this tree exist or not" and nothing else.

🦋 SYNOPSIS 🦋

#include <bltTree.h>

int
Blt_TreeExists(interp, name)

🎀 ARGUMENTS 🎀

• Tcl_Interp *interp (in) — the interpreter, and it's here so we can figure out your current namespace context. it's giving "where am i rn" energy 🧭
• const char *name (in) — the name of an existing tree data object. and yes, it can be qualified by a namespace, so go off with your fred::myTree moment 💅

👑 DESCRIPTION 👑

so this procedure right here? it determines if a C-based tree data object exists under a given name. simple as that. and here's the rundown of the args, no gatekeeping:

• interp — used the determine the current namespace context. (yes, that's what the original says, we're not touching it, periodt ✋)
• name — the name of an existing tree data object. name can be qualified by a namespace, like for example fred::myTree. and here's the tea 🍵: if you don't use a namespace qualifier, then the current namespace gets searched first, and after that the global namespace gets searched too. so it checks local before going global. main character behaviour honestly.

⭐ RETURNS ⭐

you get back a boolean result 🫶

• if the tree exists → 1 is returned 💚
• otherwise → 0 😭

that's it, no grey area, no "it depends", just a very decisive 1 or 0.

🌈 EXAMPLE 🌈

here's the moment you've been waiting for — checking if a tree called "myTree" exists:

if (!Blt_TreeExists(interp, "myTree")) {
    fprintf(stderr, "can't find tree \"myTree\\n");
}

like, if it does not exist, we scream about it to stderr. drama! iconic! ✨

🔥 KEYWORDS 🔥

tree, token Tcl_TreeCreate, Tcl_TreeGetToken, Tcl_TreeReleaseToken

and that's the whole page, bestie — you're officially a Blt_TreeExists girlie now 💜

this little slice of the manual is from BLT 2.5, dated Blt_TreeExists(3), so shoutout to the BLT era for keeping it cute and keeping it simple 🎀💖🦋