Function rb_define_class_variable 

pub unsafe extern "C" fn rb_define_class_variable(
    arg1: VALUE,
    arg2: *const c_char,
    arg3: VALUE,
)

@alias{rb_cv_set}

@internal

Am I missing something? Why we have the same thing in different names?

Generated by rb-sys for Ruby mri-x86_64-linux-gnu-3.2.3