# What are the parameters CanardOnTransferReception on\_reception and CanardShouldAcceptTransfer should\_accept in canardInit?

**URL:** <https://forum.opencyphal.org/t/what-are-the-parameters-canardontransferreception-on-reception-and-canardshouldaccepttransfer-should-accept-in-canardinit/449>\
**Category:** Libcanard\
**Created:** [April 16, 2019, 6:03am UTC](https://forum.opencyphal.org/t/what-are-the-parameters-canardontransferreception-on-reception-and-canardshouldaccepttransfer-should-accept-in-canardinit/449 "2019-04-16T06:03:54Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![YGQ](https://forum.opencyphal.org/letter_avatar_proxy/v4/letter/y/97f17d/32.png) [@YGQ](https://forum.opencyphal.org/u/YGQ)\
**Post date:** [April 16, 2019, 6:03am UTC](https://forum.opencyphal.org/t/what-are-the-parameters-canardontransferreception-on-reception-and-canardshouldaccepttransfer-should-accept-in-canardinit/449/1 "2019-04-16T06:03:54Z")

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How should these two parameters be understood?

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**Author:** ![pavel.kirienko](https://forum.opencyphal.org/user_avatar/forum.opencyphal.org/pavel.kirienko/32/9_2.png) [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\
**Post date:** [August 1, 2019, 10:08pm UTC](https://forum.opencyphal.org/t/what-are-the-parameters-canardontransferreception-on-reception-and-canardshouldaccepttransfer-should-accept-in-canardinit/449/2 "2019-08-01T22:08:34Z")

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Sorry that your question was looked over! These are pointers to callback handlers. `on_reception` is invoked when a new transfer is received (and validated for data integrity) by libcanard. `should_accept` is invoked when libcanard receives a new transfer and it needs to understand if the transfer is of interest to the application. This is actually explained in the docs:

> <https://github.com/UAVCAN/libcanard/blob/4244b8c0b303ac02a20fd603844179809bee59b3/canard.h#L164-L186>