Want to build openthread for linux - c++

Question

I want to build openthread for Linux (POSIX) and using the library, I want to develop a CoAP client application.
Right now I have disabled UDP_FORWARD in Makefile-posix and enabled OPENTHREAD_CONFIG_PLATFORM_UDP_ENABLE 1 in src/core/config/platform.h file.
My build is failing with the following error:
Making all in apps Making all in cli CC ot_cli_ftd-main.o C
C ot_cli_mtd-main.o CCLD ot-cli-mtd CCLD ot-cli-ftd
../../../src/core/libopenthread-mtd.a(libopenthread_mtd_a-udp6.o): In
function `ot::Ip6::UdpSocket::Open(void (*)(void*, otMessage*,
otMessageInfo const*), void*)':
/home/projects/KNX/openthread/examples/../src/core/net/udp6.cpp:84:
undefined reference to `otPlatUdpSocket'
../../../src/core/libopenthread-mtd.a(libopenthread_mtd_a-udp6.o): In
function `ot::Ip6::UdpSocket::Bind(ot::Ip6::SockAddr const&)':
/home/projects/KNX/openthread/examples/../src/core/net/udp6.cpp:107:
undefined reference to `otPlatUdpBind'
../../../src/core/libopenthread-mtd.a(libopenthread_mtd_a-udp6.o): In
function `ot::Ip6::UdpSocket::Close()':
/home/projects/KNX/openthread/examples/../src/core/net/udp6.cpp:141:
undefined reference to `otPlatUdpClose'
../../../src/core/libopenthread-mtd.a(libopenthread_mtd_a-udp6.o): In
function `ot::Ip6::UdpSocket::SendTo(ot::Message&,
ot::Ip6::MessageInfo const&)':
/home/projects/KNX/openthread/examples/../src/core/net/udp6.cpp:193:
undefined reference to `otPlatUdpSend'
../../../src/core/libopenthread-mtd.a(libopenthread_mtd_a-udp6.o): In
function `ot::Ip6::UdpSocket::Bind(ot::Ip6::SockAddr const&)':
/home/projects/KNX/openthread/examples/../src/core/net/udp6.cpp:114:
undefined reference to `otPlatUdpBind'
../../../src/core/libopenthread-mtd.a(libopenthread_mtd_a-udp6.o): In
function `ot::Ip6::UdpSocket::Connect(ot::Ip6::SockAddr const&)':
/home/projects/KNX/openthread/examples/../src/core/net/udp6.cpp:130:
undefined reference to `otPlatUdpConnect' collect2: error: ld returned
1 exit status Makefile:1284: recipe for target 'ot-cli-mtd' failed
make[5]: *** [ot-cli-mtd] Error 1 make[5]: *** Waiting for unfinished
jobs....
../../../src/core/libopenthread-ftd.a(libopenthread_ftd_a-udp6.o): In
function `ot::Ip6::UdpSocket::Open(void (*)(void*, otMessage*,
otMessageInfo const*), void*)':
/home/projects/KNX/openthread/examples/../src/core/net/udp6.cpp:84:
undefined reference to `otPlatUdpSocket'
../../../src/core/libopenthread-ftd.a(libopenthread_ftd_a-udp6.o): In
function `ot::Ip6::UdpSocket::Bind(ot::Ip6::SockAddr const&)':
/home/projects/KNX/openthread/examples/../src/core/net/udp6.cpp:107:
undefined reference to `otPlatUdpBind'
../../../src/core/libopenthread-ftd.a(libopenthread_ftd_a-udp6.o): In
function `ot::Ip6::UdpSocket::Close()':
/home/projects/KNX/openthread/examples/../src/core/net/udp6.cpp:141:
undefined reference to `otPlatUdpClose'
../../../src/core/libopenthread-ftd.a(libopenthread_ftd_a-udp6.o): In
function `ot::Ip6::UdpSocket::SendTo(ot::Message&,
ot::Ip6::MessageInfo const&)':
/home/projects/KNX/openthread/examples/../src/core/net/udp6.cpp:193:
undefined reference to `otPlatUdpSend'
../../../src/core/libopenthread-ftd.a(libopenthread_ftd_a-udp6.o): In
function `ot::Ip6::UdpSocket::Bind(ot::Ip6::SockAddr const&)':
/home/projects/KNX/openthread/examples/../src/core/net/udp6.cpp:114:
undefined reference to `otPlatUdpBind'
../../../src/core/libopenthread-ftd.a(libopenthread_ftd_a-udp6.o): In
function `ot::Ip6::UdpSocket::Connect(ot::Ip6::SockAddr const&)':
/home/projects/KNX/openthread/examples/../src/core/net/udp6.cpp:130:
undefined reference to `otPlatUdpConnect' collect2: error: ld returned
1 exit status Makefile:1280: recipe for target 'ot-cli-ftd' failed
make[5]: *** [ot-cli-ftd] Error 1 Makefile:442: recipe for target
'all-recursive' failed make[4]: *** [all-recursive] Error 1
Makefile:444: recipe for target 'all-recursive' failed make[3]: ***
[all-recursive] Error 1 Makefile:601: recipe for target
'all-recursive' failed make[2]: *** [all-recursive] Error 1
Makefile:527: recipe for target 'all' failed make[1]: *** [all] Error
2 examples/Makefile-posix:295: recipe for target
'do-build-x86_64-unknown-linux-gnu' failed make: ***
[do-build-x86_64-unknown-linux-gnu] Error 2
My ultimate goal is to use openthread library and develop a Coap Client application. Can anybody help me on this?

Answer 1

Enabling OPENTHREAD_CONFIG_PLATFORM_UDP_ENABLE requires an implementation of the otPlatUdp* APIs.
For Linux, you can look to the POSIX app https://github.com/openthread/openthread/tree/master/src/posix.