If you are writing some packet sniffing code using libpcap on Ubuntu Linux, there are higher chances you may get an error like below, during the first compilation.
sniffer.c:1:18: fatal error: pcap.h: No such file or directory
The above error shows we are missing pcap.h in current development environment, for installing this header, use below command
$ sudo apt-get install libpcap-dev
If you are looking for actual packet capturing code, you may refer to “sniffex – C program to Capture wifi packets using libpcap“