iperf3.19.so with android app integration through NDK failed with UDP test(TCP works)

[dantanqikun]

1. compiled iperf3.19.so with NDK(iperf3.19/src/configure, ndk-build NDK_APPLICATION_MK=/opt/jni/Application.mk) in ubuntu2204.
2. android studio, put generated iperf3.19.so into jniLibs folders of android project
3. create iper3_jni.cpp, to bridge java activity, oder of funciton call as following:
   iperf_defaults(test);
   iperf_set_test_role(test, 'c');
   iperf_set_verbose(test,1);
   iperf_set_test_server_hostname(test, host_str.c_str());
   iperf_set_test_server_port(test, server_port);
   iperf_set_test_duration(test, duration_sec);
   iperf_set_test_json_output(test, 1); // Enable JSON output
   set_protocol(test,Pudp);
   4.iperf_run_client(test);
   5.iperf_get_test_json_output_string(test);

BUT json_output_string records do not have metric value for UDP test:
-Transfer, Bitrate, Jitter,Lost/Total are all zero.
-time start and time end are not zeo

6. Default TCP test works with metric values
7. tested iperf3.18.so with same result

thanks for any suggestion

[dantanqikun]

i got the answer, cause udp needs to define buffer size, and block size(normally 1460) then works

[dantanqikun]

so i close it