I am writing a tool to capture the outgoing packets at a radio interface using libpcap. The device uses NXP driver and 
QNX OS.
When I set the direction as OUT in pcap_setdirection API, I am getting error from libpcap as below:

"Setting direction to PCAP_D_OUT is not supported on BPF"

However, if I set direction as PCAP_D_INOUT, it is able to capture both incoming and outgoing packets together.

Please suggest me any IOCTL or any way to enable only the outgoing packet capture.

Tcpdump also dosen't captures with only out direction.