Function svn_error_createf 

pub unsafe extern "C" fn svn_error_createf(
    apr_err: apr_status_t,
    child: *mut svn_error_t,
    fmt: *const c_char,
    ...
) -> *mut svn_error_t

Create an error structure with the given @a apr_err and @a child, with a printf-style error message produced by passing @a fmt, using apr_psprintf().