# Libcanard return codes

**URL:** <https://forum.opencyphal.org/t/libcanard-return-codes/1719>\
**Category:** Applications & Usage\
**Created:** [July 22, 2022, 5:51pm UTC](https://forum.opencyphal.org/t/libcanard-return-codes/1719 "2022-07-22T17:51:37Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![soypat](https://forum.opencyphal.org/user_avatar/forum.opencyphal.org/soypat/32/1130_2.png) [@soypat](https://forum.opencyphal.org/u/soypat)\
**Post date:** [July 22, 2022, 5:51pm UTC](https://forum.opencyphal.org/t/libcanard-return-codes/1719/1 "2022-07-22T17:51:37Z")

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I’ve been looking at the libcanard C implementation and wondering what standard is being followed for return integers of functions.

I’m also curious as to what “extent” means- is that the maximum capacity of the allocated payload pointer? The “Capacity” of sorts?

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**Author:** ![soypat](https://forum.opencyphal.org/user_avatar/forum.opencyphal.org/soypat/32/1130_2.png) [@soypat](https://forum.opencyphal.org/u/soypat)\
**Post date:** [July 22, 2022, 8:40pm UTC](https://forum.opencyphal.org/t/libcanard-return-codes/1719/2 "2022-07-22T20:40:08Z")

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OK, I just figured out how C headers work. Looks like all the documentation is there in canard.h. Was wondering why the source code was so sparsely documented.