list_first_entry_or_null(9) [centos man page]

LIST_FIRST_ENTRY_OR_(9) 					    Data Types						   LIST_FIRST_ENTRY_OR_(9)

NAME

       list_first_entry_or_null - get the first element from a list

SYNOPSIS

       list_first_entry_or_null(ptr, type, member);

ARGUMENTS

       ptr
	   the list head to take the element from.

       type
	   the type of the struct this is embedded in.

       member
	   the name of the list_struct within the struct.

DESCRIPTION

       Note that if the list is empty, it returns NULL.

COPYRIGHT

Kernel Hackers Manual 3.10					     June 2014						   LIST_FIRST_ENTRY_OR_(9)

PCAP_FINDALLDEVS(3)					     Library Functions Manual					       PCAP_FINDALLDEVS(3)

NAME

       pcap_findalldevs - get a list of capture devices

SYNOPSIS

       #include <pcap/pcap.h>

       char errbuf[PCAP_ERRBUF_SIZE];

       int pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf);

DESCRIPTION

       pcap_findalldevs() constructs a list of network devices that can be opened with pcap_create() and pcap_activate() or with pcap_open_live().
       (Note that there may be network devices that cannot be opened by the process calling pcap_findalldevs(), because, for example, that process
       might  not  have  sufficient  privileges to open them for capturing; if so, those devices will not appear on the list.)	alldevsp is set to
       point to the first element of the list; each element of the list is of type pcap_if_t, and has the following members:

	      next   if not NULL, a pointer to the next element in the list; NULL for the last element of the list

	      name   a pointer to a string giving a name for the device to pass to pcap_open_live()

	      description
		     if not NULL, a pointer to a string giving a human-readable description of the device

	      addresses
		     a pointer to the first element of a list of addresses for the interface

	      flags  interface flags:

		     PCAP_IF_LOOPBACK
			    set if the interface is a loopback interface

       Each element of the list of addresses is of type pcap_addr_t, and has the following members:

	      next   if not NULL, a pointer to the next element in the list; NULL for the last element of the list

	      addr   a pointer to a struct sockaddr containing an address

	      netmask
		     if not NULL, a pointer to a struct sockaddr that contains the netmask corresponding to the address pointed to by addr

	      broadaddr
		     if not NULL, a pointer to a struct sockaddr that contains the broadcast address corresponding to the address  pointed  to	by
		     addr; may be null if the interface doesn't support broadcasts

	      dstaddr
		     if  not NULL, a pointer to a struct sockaddr that contains the destination address corresponding to the address pointed to by
		     addr; may be null if the interface isn't a point-to-point interface

       Note that not all the addresses in the list of addresses are necessarily IPv4 or IPv6 addresses - you must check the  sa_family	member	of
       the struct sockaddr before interpreting the contents of the address.

       The list of devices must be freed with pcap_freealldevs().

RETURN VALUE

       pcap_findalldevs()  returns  0  on  success  and  -1 on failure.  If -1 is returned, errbuf is filled in with an appropriate error message.
       errbuf is assumed to be able to hold at least PCAP_ERRBUF_SIZE chars.

SEE ALSO

       pcap(3), pcap_create(3), pcap_activate(3), pcap_open_live(3), pcap_freealldevs(3)

								   5 April 2008 					       PCAP_FINDALLDEVS(3)