pcap_init — Npcap API

Name

pcap_init - initialize the library

Synopsis

#include <pcap/pcap.h>
char errbuf[PCAP_ERRBUF_SIZE];
int pcap_init(unsigned int opts, char *errbuf);

Description

pcap_init() is used to initialize the Packet Capture library. opts specifies options for the library; currently, the options are:

PCAP_CHAR_ENC_LOCAL Treat all strings supplied as arguments, and return all strings to the caller, as being in the local character encoding.

PCAP_CHAR_ENC_UTF_8 Treat all strings supplied as arguments, and return all strings to the caller, as being in UTF-8.

On UNIX-like systems, the local character encoding is assumed to be UTF-8, so no character encoding transformations are done.

On Windows, the local character encoding is the local ANSI code page.

If pcap_init() is not called, strings are treated as being in the local ANSI code page on Windows, pcap_lookupdev(3PCAP) will succeed if there is a device on which to capture, and pcap_create(3PCAP) makes an attempt to check whether the string passed as an argument is a UTF-16LE string - note that this attempt is unsafe, as it may run past the end of the string - to handle pcap_lookupdev() returning a UTF-16LE string. Programs that don't call pcap_init() should, on Windows, call pcap_wsockinit() to initialize Winsock; this is not necessary if pcap_init() is called, as pcap_init() will initialize Winsock itself on Windows.

Return value

pcap_init() returns 0 on success and PCAP_ERROR on failure. If PCAP_ERROR 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.

Backward compatibility

This function became available in libpcap release 1.9.0. In previous releases, on Windows, all strings supplied as arguments, and all strings returned to the caller, are in the local character encoding.