pcre2_set_optimize - Man Page

#include <pcre2.h>

int pcre2_set_optimize(pcre2_compile_context *ccontext,
  uint32_t directive);

This function controls which performance optimizations will be applied by pcre2_compile(). It can be called multiple times with the same compile context; the effects are cumulative, with the effects of later calls taking precedence over earlier ones.

The result is zero for success, PCRE2_ERROR_NULL if ccontext is NULL, or PCRE2_ERROR_BADOPTION if directive is unknown. The latter could be useful to detect if a certain optimization is available.

The list of possible values for the directive parameter are:

 PCRE2_OPTIMIZATION_FULL   Enable all optimizations (default)
 PCRE2_OPTIMIZATION_NONE   Disable all optimizations
 PCRE2_AUTO_POSSESS        Enable auto-possessification
 PCRE2_AUTO_POSSESS_OFF    Disable auto-possessification
 PCRE2_DOTSTAR_ANCHOR      Enable implicit dotstar anchoring
 PCRE2_DOTSTAR_ANCHOR_OFF  Disable implicit dotstar anchoring
 PCRE2_START_OPTIMIZE      Enable start-up optimizations at match time
 PCRE2_START_OPTIMIZE_OFF  Disable start-up optimizations at match time

There is a complete description of the PCRE2 native API, including detailed descriptions directive parameter values in the pcre2api page.