text: Next: Running Protoize, Previous: Environment Variables, Up: Invoking GCC -x option to make the driver treat it as a C or C++ header file. You will probably want to use a tool like make to keep the precompiled header up-to-date when the headers it contains change.
  A precompiled header file will be searched for when
  #include is
  seen in the compilation. As it searches for the included file
  (see Search Path) the
  compiler looks for a precompiled header in each directory just before it
  looks for the include file in that directory. The name searched for is
  the name specified in the
  #include with `.gch' appended. If
  the precompiled header file can't be used, it is ignored.
  For instance, if you have
  #include "all.h", and you have
  all.h.gch in the same directory as all.h, then the
  precompiled header file will be used if possible, and the original
  header will:
  
   will be a mixture of the behavior for the options. For instance, if you use -g to generate the precompiled header but not when using it, you may or may not get debugging information for routines in the precompiled header.