Api function
#include <idn2.h>
void idn2_free(void * ptr);
pointer to deallocate
Call free(3) on the given pointer.
This function is typically only useful on systems where the library malloc heap is different from the library caller malloc heap, which happens on Windows when the library is a separate DLL.
The full documentation for libidn2 is maintained as a Texinfo manual. If the info and libidn2 programs are properly installed at your site, the command
info libidn2
should give you access to the complete manual.