PCAP_INIT(3PCAP)

🌸 NAME 🌸

pcap_init — initialize the library. This is the PCAP_INIT(3PCAP) manual page, bestie, and it's literally the "wake up the Packet Capture library" function 💖

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✨ SYNOPSIS ✨

#include <pcap/pcap.h>

char errbuf[PCAP_ERRBUF_SIZE];

int pcap_init(unsigned int opts, char *errbuf);

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💖 DESCRIPTION 💖

Okay so pcap_init() is used to initialize the Packet Capture library. The opts argument specifies options for the library, and errbuf is a buffer large enough to hold at least PCAP_ERRBUF_SIZE chars. Slay 🎀

Currently, the options that can be specified in opts 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. Periodt.

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

Now, the plot twist: 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.

⚠️ bestie, note that this attempt is unsafe, as it may run past the end of the string — and it's there to handle pcap_lookupdev() returning a UTF-16LE string. Not me side-eyeing that 🙈

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. The way that's a whole load off your plate 🫶

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🦋 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. Lowkey helpful, highkey iconic 💅

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🌈 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. Fr fr, ancient history 🦋

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🎀 SEE ALSO 🎀

pcap(3PCAP) — that's the one, bestie 👑

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okay that's the whole PCAP_INIT(3PCAP) page, dated 30 November 2023 — mwah, go initialize something cute 💋💖