pcre_jit_stack_free man page
PCRE — Perl-compatible regular expressions
void pcre_jit_stack_free(pcre_jit_stack *stack);
void pcre16_jit_stack_free(pcre16_jit_stack *stack);
void pcre32_jit_stack_free(pcre32_jit_stack *stack);
This function is used to free a JIT stack that was created by pcre[16|32]_jit_stack_alloc() when it is no longer needed. For more details, see the pcrejit page.
There is a complete description of the PCRE native API in the pcreapi page and a description of the POSIX API in the pcreposix page.