freebsd-src/contrib/libpcap/pcap_init.3pcap
Joseph Mingrone 6f9cba8f8b
libpcap: Update to 1.10.3
Local changes:

- In contrib/libpcap/pcap/bpf.h, do not include pcap/dlt.h.  Our system
  net/dlt.h is pulled in from net/bpf.h.
- sys/net/dlt.h: Incorporate changes from libpcap 1.10.3.
- lib/libpcap/Makefile: Update for libpcap 1.10.3.

Changelog:	https://git.tcpdump.org/libpcap/blob/95691ebe7564afa3faa5c6ba0dbd17e351be455a:/CHANGES
Reviewed by:	emaste
Obtained from:	https://www.tcpdump.org/release/libpcap-1.10.3.tar.gz
Sponsored by:	The FreeBSD Foundation
2023-03-31 16:02:22 -03:00

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.\" Copyright (c) 1994, 1996, 1997
.\" The Regents of the University of California. All rights reserved.
.\"
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.\" ``This product includes software developed by the University of California,
.\" Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
.\" the University nor the names of its contributors may be used to endorse
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.\" written permission.
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.TH PCAP_INIT 3PCAP "4 May 2022"
.SH NAME
pcap_init \- initialize the library
.SH SYNOPSIS
.nf
.ft B
#include <pcap/pcap.h>
.ft
.LP
.nf
.ft B
char errbuf[PCAP_ERRBUF_SIZE];
.ft
.LP
.ft B
int pcap_init(unsigned int opts, char *errbuf);
.ft
.fi
.SH DESCRIPTION
.BR pcap_init ()
is used to initialize the Packet Capture library.
.I opts
specifies options for the library;
currently, the options are:
.TP
.B PCAP_CHAR_ENC_LOCAL
Treat all strings supplied as arguments, and return all strings to the
caller, as being in the local character encoding.
.TP
.B PCAP_CHAR_ENC_UTF_8
Treat all strings supplied as arguments, and return all strings to the
caller, as being in UTF-8.
.PP
On UNIX-like systems, the local character encoding is assumed to be
UTF-8, so no character encoding transformations are done.
.PP
On Windows, the local character encoding is the local ANSI code page.
.PP
If
.BR pcap_init ()
is not called, strings are treated as being in the local ANSI code page
on Windows,
.BR pcap_lookupdev (3PCAP)
will succeed if there is a device on which to capture, and
.BR 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
.BR pcap_lookupdev ()
returning a UTF-16LE string. Programs that don't call
.BR pcap_init ()
should, on Windows, call
.BR pcap_wsockinit ()
to initialize Winsock; this is not necessary if
.BR pcap_init ()
is called, as
.BR pcap_init ()
will initialize Winsock itself on Windows.
.SH RETURN VALUE
.BR pcap_init ()
returns
.B 0
on success and
.B PCAP_ERROR
on failure.
If
.B PCAP_ERROR
is returned,
.I errbuf
is filled in with an appropriate error message.
.I errbuf
is assumed to be able to hold at least
.B PCAP_ERRBUF_SIZE
chars.
.SH 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.
.SH SEE ALSO
.BR pcap (3PCAP)