rtapi_app_main(3rtapi)

✨ rtapi_app_main ✨

okay bestie, so this is rtapi_app_main(3rtapi) — it lives in the HAL corner of the LinuxCNC manual universe, and it's literally the function YOU write to get your component born into the world. 👑

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🌸 NAME 🌸

rtapi_app_main — the user-provided function that initializes a component 💖

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🎀 SYNTAX 🎀

#include <rtapi_app.h>

int rtapi_app_main(void) {...}

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🫶 ARGUMENTS 🫶

None. Nada. Zero. It takes no arguments, she's low-maintenance like that. 💅

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🦋 DESCRIPTION 🦋

So here's the tea: rtapi_app_main is your function. Like, the component author writes the body of it. That's you, bestie. ✨

And what goes in that body? Generally it's a call to rtapi_init or hal_init, and then after that comes all the other component-specific initialization code you need. That's the whole vibe — you're basically rolling out the red carpet so your component can make its grand entrance. 🌈

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💜 RETURN VALUE 💜

• Return 0 for success. slay. ✅
• Return a negative errno value (e.g., -EINVAL) on error. 🚨

ngl, existing code also returns RTAPI or HAL error values, and that's fine — but here's the thing: using negative errno values gives you better diagnostics from insmod. so do that if you can. iykyk. 🫶

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🔥 REALTIME CONSIDERATIONS 🔥

This gets called automatically by the rtapi infrastructure, and it happens in an initialization context — which is to say, NOT realtime. so no panicking about your realtime budget here, she's off duty. 😌

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⭐ SEE ALSO ⭐

• rtapi_app_exit(3rtapi)
• rtapi_init(3rtapi)
• hal_init(3hal)

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and that's the whole page, bestie!! 🎀 go forth and init your components. the LinuxCNC Documentation wrote this one back on 2008-05-26, and it's still out here being iconic in the rtapi_app_main(3rtapi) era. mwah. 💖🦋✨