osf1 man page for pfopen

pfopen(3)						     Library Functions Manual							 pfopen(3)

NAME
       pfopen - Open a packet filter file

SYNOPSIS
       pfopen(ifname, flags)

       char *ifname; int flags;

DESCRIPTION
       The  packet filter (see packetfilter(7)) provides raw access to Ethernets and similar network data link layers.	The routine pfopen is used
       to open a packet filter file descriptor.  The routine hides various details about the way packet filter files are opened and named.

       The ifname argument is a pointer to a null-terminated string containing the name of the interface for which the application is opening  the
       packet  filter.	 This name may be the name of an actual interface on the system (for example, ln0) or it may be a pseudo-interface name of
       the form pfn, used to specify the nth interface attached to the system.	For example, pf0 specifies the first such interface.  If ifname is
       NULL, the default interface (pf0) is used.

       The flags argument has the same meaning as the corresponding argument to the open(2) system call.

       The file descriptor returned by pfopen is otherwise identical to one returned by open(2).

ERRORS
       The pfopen routine returns a negative integer if the file could not be opened.  This may be because of resource limitations, or because the
       specified interface does not exist.

RELATED INFORMATION
       Commands: open(2)

       Files: bpf(7), packetfilter(7) delim off

																	 pfopen(3)