PUREFUNC          125 .ext/include/x86_64-linux/ruby/config.h #define PUREFUNC(x) __attribute__ ((__pure__)) x
PUREFUNC         2035 gc.c           PUREFUNC(static inline int is_pointer_to_heap(rb_objspace_t *objspace, void *ptr);)
PUREFUNC           30 include/ruby/defines.h # define PUREFUNC(x) x