Vedis Built-in Commands - Key/Value.
Set key to hold string value if key does not exist. In that case, it is equal to SET. When key already holds a value, no operation is performed. SETNX is short for "SET if N ot e X ists".
Refer to the download page for some C/C++ samples on how to invoke this command from your host application.
vedis> SETNX message "Greeting!"
vedis> SETNX message "Bye Bye"
vedis> MGET test message