求助:missing function header

编译时,下面的代码包了missing function header的错误:error C2447: missing function header (old-style formal list?),这到底是怎么回事啊....大家帮忙看看...



/* in/out macros */
#define OUTPUT_BIGNUM(num, out, y, z)
{
if ((y + 4) > *outlen) { return CRYPT_BUFFER_OVERFLOW; }
z = (unsigned long)mp_unsigned_bin_size(num);
STORE32L(z, out+y);
y += 4;
if ((y + z) > *outlen) { return CRYPT_BUFFER_OVERFLOW; }
if ((err = mp_to_unsigned_bin(num, out+y)) != MP_OKAY) { return mpi_to_ltc_error(err); }
y += z;
}