hal_set_constructor(3hal)

💖 hal_set_constructor(3hal) 💖

okay bestie, so this is a page from the HAL manual section, and it's literally all about hal_set_constructor — the lil function that sets the constructor function for this component. yes we're doing C-level matchmaking today, stay with me 🫶

✨ NAME ✨

hal_set_constructor — sets the constructor function for this component. that's it, that's the whole job, and she does it flawlessly 💅

🌈 SYNTAX 🌈

typedef int (*hal_constructor_t)(const char *prefix, const char *arg);
       int hal_set_constructor(int comp_id, hal_constructor_t
       constructor)

look at that. two whole declarations. one of them is the type, one of them is the function you're actually calling. no cap 🔥

🎀 ARGUMENTS 🎀

• comp_id — a HAL component identifier that came back from an earlier call to hal_init. yes, you need to have already done the hal_init thing, this is not a first-date situation, it's a second-date situation 💜
• prefix — the prefix that gets given to the pins, parameters, and functions in the new instance. it's giving name tag energy, but for pins 🏷️
• arg — an argument that may be used by the component to customize this instance. "may be used" — so it's optional-ish in spirit, but like, it's right there in the signature, so 😌

🦋 DESCRIPTION 🦋

okay so here's the tea. as an experimental feature in HAL 2.1, components may be constructable 👑

which means a component like this can create pins and parameters — not only at the time the module is loaded, but it may also create additional pins and parameters, and functions, on demand. on demand!! main character behavior fr fr ✨

lowkey important: this is marked as experimental in the original. so like, respect the label, bestie 🫶

⭐ RETURN VALUE ⭐

returns a HAL status code. that's the whole answer. check it, don't ignore it, she's telling you something 🌸

🌸 SEE ALSO 🌸

• halcmd(1)

kisses, mwah 💋 this page was brought to you by the LinuxCNC Documentation, dated 2006-10-12, and it lives in the 3hal manual section, so you know exactly where to find her when you need her again. bye bestie, go build something iconic 👑🦋