the vector
  <i>bytes</i>            the serialized byte stream
  <i>gcontext</i>         pointer to a general context or NULL
</pre>
The <i>bytes</i> argument must point to a block of data that was originally
created by <b>pcre2_serialize_encode()</b>, though it may have been saved on
disc or elsewhere in the meantime. If there are more codes in the serialized
data than slots in the list, only those compiled patterns that will fit are
decoded. The yield of the function is the number of decoded patterns, or