Checking the syntax involves opening a device, which 1) might not succeed and 2) might tie up a BPF device or otherwise consume resources so we leave it up to the capture operation to do the checking. svn path=/trunk/; revision=12225
Set svn:keywords to Id to expand RCS IDs. Include <string.h> to declare "strcmp()" and "strlen()". svn path=/trunk/; revision=12126
svn path=/trunk/; revision=12123