Function mupdf_sys::fz_set_warning_callback

pub unsafe extern "C" fn fz_set_warning_callback(
    ctx: *mut fz_context, 
    print: Option<unsafe extern "C" fn(user: *mut c_void, message: *const c_char)>, 
    user: *mut c_void
)

Set the warning callback. This will be called as part of the exception handling.

The callback must not throw exceptions!