File: m4.info,  Node: Frozen state,  Next: Debugging options,  Prev: Limits control,  Up: Invoking m4

2.4 Command line options for frozen state
=========================================

GNU ‘m4’ comes with a feature of freezing internal state (*note 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.