---
name: "pcre2_substring_length_bynumber"
section: "3"
platform: "linux"
package: "pcre2"
version: "10.49-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/pcre2_substring_length_bynumber"
---

# pcre2\_substring\_length\_bynumber(3)

Perl-compatible regular expressions (revised API)

## NAME

PCRE2 - Perl-compatible regular expressions (revised API)

## SYNOPSIS

**#include \<pcre2.h\>**

```
int pcre2_substring_length_bynumber(pcre2_match_data *match_data,
  uint32_t number, PCRE2_SIZE *length);
```

## DESCRIPTION

This function returns the length of a matched substring, identified by number. The arguments are:

  *match\_data*   The match data block for the match\
   *number*       The substring number\
   *length*       Where to return the length, or NULL

The third argument may be NULL if all you want to know is whether or not a substring is set. The yield is zero on success, or a negative error code otherwise. After a partial match, only substring 0 is available.

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.