al_cstr - Allegro 5 API

       Get  a  char  *  pointer  to  the  data  in  a  string.   This  pointer  will  only  be  valid  while the
       ALLEGRO_USTR(3alleg5) object is not modified and not destroyed.  The pointer may be passed  to  functions
       expecting C-style strings, with the following caveats:

       • ALLEGRO_USTRs  are  allowed  to  contain  embedded  NUL  ('\0')  bytes.  That means al_ustr_size(u) and
         strlen(al_cstr(u)) may not agree.

       • An ALLEGRO_USTR may be created in such a way that  it  is  not  NUL  terminated.   A  string  which  is
         dynamically  allocated  will  always  be  NUL  terminated,  but a string which references the middle of
         another string or region of memory will not be NUL terminated.

       • If the ALLEGRO_USTR references another string, the returned C string will  point  into  the  referenced
         string.  Again, no NUL terminator will be added to the referenced string.

       al_cstr - Allegro 5 API

al_ustr_to_buffer(3alleg5), al_cstr_dup(3alleg5)

Allegro reference manual                                                                        al_cstr(3alleg5)

              #include <allegro5/allegro.h>

              const char *al_cstr(const ALLEGRO_USTR *us)