2.4 Command line options for frozen state

GNU m4 comes with a feature of freezing internal state (see Frozen files). This can be used to speed up m4 execution when reusing a common initialization script.

-F FILE

--freeze-state=FILE

Once execution is finished, write out the frozen state on the specified FILE. It is conventional, but not required, for FILE to end in `.m4f'.

-R FILE

--reload-state=FILE

Before execution starts, recover the internal state from the specified frozen FILE. The options -D, -U, and -t take effect after state is reloaded, but before the input files are read.