PCAP_INIT(3)

💖 NAME 💖

okay so welcome to the Library Functions Manual, bestie — this page is PCAP_INIT(3), and the main character is pcap_init, the function that initializes the library. Fr fr, it's giving setup era. ✨

✨ 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; errbuf is a buffer large enough to hold at least PCAP_ERRBUF_SIZE chars.

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. Local encoding rights! 💅
• PCAP_CHAR_ENC_UTF_8 — treat all strings supplied as arguments, and return all strings to the caller, as being in UTF-8. UTF-8 rights, iykyk. 🌈

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

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

If pcap_init() is not called, strings are treated as being in the local ANSI code page on Windows, pcap_lookupdev(3) will succeed if there is a device on which to capture, and pcap_create(3) 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.

⚠️ bestie, that unsafe check is not a vibe: the attempt may run past the end of the string. No cap, be careful.

🌸 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. So check that errbuf, periodt. 💖

🎀 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. History lesson, slay. 🦋

🌈 SEE ALSO 🌈

• pcap(3)

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cute sign-off: page PCAP_INIT(3), dated 30 November 2023 — signed, sealed, delivered, and fully initialized 💅✨