PCRE2_PATTERN_INFO(3)

💖 PCRE2_PATTERN_INFO(3) 💖

bestie, welcome to the PCRE2 Library Functions Manual — no cap, this one is all about peeking at the info inside a compiled pattern. ✨

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🎀 NAME 🎀

PCRE2 - Perl-compatible regular expressions (revised API)

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✨ SYNOPSIS ✨

okay so, the synopsis is literally:

#include <pcre2.h>

int pcre2_pattern_info(const pcre2_code *code, uint32_t what,
   void *where);

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💅 DESCRIPTION 💅

This function returns information about a compiled pattern. Its arguments are giving:

• code — Pointer to a compiled regular expression pattern
• what — What information is required
• where — Where to put the information

🌸 recognized what values 🌸

The recognized values for the what argument, and the information they request, are as follows:

• PCRE2_INFO_ALLOPTIONS — Final options after compiling
• PCRE2_INFO_ARGOPTIONS — Options passed to pcre2_compile()
• PCRE2_INFO_BACKREFMAX — Number of highest backreference
• PCRE2_INFO_BSR — What \R matches:
  • PCRE2_BSR_UNICODE — Unicode line endings
  • PCRE2_BSR_ANYCRLF — CR, LF, or CRLF only
• PCRE2_INFO_CAPTURECOUNT — Number of capturing subpatterns
• PCRE2_INFO_DEPTHLIMIT — Backtracking depth limit if set, otherwise PCRE2_ERROR_UNSET
• PCRE2_INFO_EXTRAOPTIONS — Extra options that were passed in the compile context
• PCRE2_INFO_FIRSTBITMAP — Bitmap of first code units, or NULL
• PCRE2_INFO_FIRSTCODETYPE — Type of start-of-match information:
  • 0 — nothing set
  • 1 — first code unit is set
  • 2 — start of string or after newline
• PCRE2_INFO_FIRSTCODEUNIT — First code unit when type is 1
• PCRE2_INFO_FRAMESIZE — Size of backtracking frame
• PCRE2_INFO_HASBACKSLASHC — Return 1 if pattern contains \C
• PCRE2_INFO_HASCRORLF — Return 1 if explicit CR or LF matches exist in the pattern
• PCRE2_INFO_HEAPLIMIT — Heap memory limit if set, otherwise PCRE2_ERROR_UNSET
• PCRE2_INFO_JCHANGED — Return 1 if (?J) or (?-J) was used
• PCRE2_INFO_JITSIZE — Size of JIT compiled code, or 0
• PCRE2_INFO_LASTCODETYPE — Type of must-be-present information:
  • 0 — nothing set
  • 1 — code unit is set
• PCRE2_INFO_LASTCODEUNIT — Last code unit when type is 1
• PCRE2_INFO_MATCHEMPTY — 1 if the pattern can match an empty string, 0 otherwise
• PCRE2_INFO_MATCHLIMIT — Match limit if set, otherwise PCRE2_ERROR_UNSET
• PCRE2_INFO_MAXLOOKBEHIND — Length (in characters) of the longest lookbehind assertion
• PCRE2_INFO_MINLENGTH — Lower bound length of matching strings
• PCRE2_INFO_NAMECOUNT — Number of named subpatterns
• PCRE2_INFO_NAMEENTRYSIZE — Size of name table entries
• PCRE2_INFO_NAMETABLE — Pointer to name table
• PCRE2_CONFIG_NEWLINE — Code for the newline sequence:
  • PCRE2_NEWLINE_CR
  • PCRE2_NEWLINE_LF
  • PCRE2_NEWLINE_CRLF
  • PCRE2_NEWLINE_ANY
  • PCRE2_NEWLINE_ANYCRLF
  • PCRE2_NEWLINE_NUL
• PCRE2_INFO_RECURSIONLIMIT — Obsolete synonym for PCRE2_INFO_DEPTHLIMIT
• PCRE2_INFO_SIZE — Size of compiled pattern

🦋 the where pointer tea 🦋

If where is NULL, the function returns the amount of memory needed for the requested information, in bytes. Otherwise, the where argument must point to an unsigned 32-bit integer (uint32_t variable), except for the following what values, when it must point to a variable of the type shown:

• PCRE2_INFO_FIRSTBITMAP — const uint8_t *
• PCRE2_INFO_JITSIZE — size_t
• PCRE2_INFO_NAMETABLE — PCRE2_SPTR
• PCRE2_INFO_SIZE — size_t

🌈 return values / yield 🌈

The yield of the function is zero on success or:

• PCRE2_ERROR_NULL — the argument code is NULL
• PCRE2_ERROR_BADMAGIC — the "magic number" was not found
• PCRE2_ERROR_BADOPTION — the value of what is invalid
• PCRE2_ERROR_BADMODE — the pattern was compiled in the wrong mode
• PCRE2_ERROR_UNSET — the requested information is not set

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There is a complete description of the PCRE2 native API in the pcre2api page and a description of the POSIX API in the pcre2posix page.

bestie, that’s literally the whole page 💖 no cap.

okay bye bestie 🫶 — this manual page is from PCRE2 10.47, dated 14 February 2019. 💅