Transactions and Savepoints - Mailing list pgsql-php

Hello,

I have a problem with savepoints.

I have a function which does some DB changed. This changes have to be in
  a single Transaction. This function is now called in two different
ways. Once within a transaction and once not in a transaction. But how
can i check if I am within a transaction, so I  can start a new
transaction or set a savepoint.

Is there a way to check this?

Thanks and Greetings,

Stefan Sturm