How to automatically put FloatBarrier before and after each section

Question

I am looking for a command like:

\alwaysFloatBarrier

Such that whenever I write a normal section or subsection or subsubsection:

\section{Example 1}

\subsection{Example 2}

\subsubsection{Example 3}

They get automatically converted to:

\FloatBarrier
\section{Example 1}
\FloatBarrier

\FloatBarrier
\subsection{Example 2}
\FloatBarrier

\FloatBarrier
\subsubsection{Example 3}
\FloatBarrier

Answer 1

You could achieve your objective by loading the placeins package (for the \FloatBarrier macro) along with the etoolbox package (for the \pretocmd macro) and issuing the instructions

\pretocmd{\section}{\FloatBarrier}{}{}
\pretocmd{\subsection}{\FloatBarrier}{}{}
\pretocmd{\subsubsection}{\FloatBarrier}{}{}

in the preamble. If you need this in macro form, you could write

\newcommand\alwaysFloatBarrier{%
   \pretocmd{\section}{\FloatBarrier}{}{}%
   \pretocmd{\subsection}{\FloatBarrier}{}{}%
   \pretocmd{\subsubsection}{\FloatBarrier}{}{}%
}

and then issue the instruction \alwaysFloatBarrier.

Answer 2

You have not said but I assume you mean the command from the placeins package, in which case \usepackage[section]{placeins} does what you need.

A lat this dos what is asked for in the title, for sections, it does not automatically do the same for subsections, but forcing page breaks at the lower order headings isn't usually desirable.