A well-known adult entertainment lawyer has raised the question on his blog concerning FOSTA.  So far, the Congress.gov  does not yet show its been signed by Trump.   The time has passed for him to sign so if he hasn't it may have just been a "pocket veto". Or while I don't understand the significance the Senate may have held it back and not given it to him to avoid a veto, but doesn't make sense to me how that would work.  

nothing with Trump is predictable, except that he is likely to do something no other President has done.

The legal rule is delineated in the US Constitution which is dependent on if the Congress is in session or not.  See Article 1, Section 7:

There is a legal question whether Congress is out of session of just in recess until next week.  The Senate may not have sent the bill to Trump to be sure it is in session.

Hasn't been submitted to the President yet.   He will no doubt sign it.  So would Hillary, had she been elected.  It would likely have been passed months ago if she were in office, and be even more draconian.  Since when have feminists been friendly to the hobby?  Not to forget mentioning, she's as establishment as it gets.  The lawyers are going to make a killing off of this bill once the avalanche of lawsuits begins.  Whose side do you think she'd be on?    

So he has 10 days excluding Sunday to respond.