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B::C(3)


NAME

  B::C - Perl compiler's C backend


SYNOPSIS

	  perl -MO=C[,OPTIONS] foo.pl


DESCRIPTION

  This compiler backend takes Perl source and generates C source code
  corresponding to the internal structures that perl uses to run your
  program. When the generated C source is compiled and run, it cuts out the
  time which perl would have taken to load and parse your program into its
  internal semi-compiled form. That means that compiling with this backend
  will not help improve the runtime execution speed of your program but may
  improve the start-up time.  Depending on the environment in which your
  program runs this may be either a help or a hindrance.


OPTIONS

  If there are any non-option arguments, they are taken to be names of
  objects to be saved (probably doesn't work properly yet).  Without extra
  arguments, it saves the main program.

  -ofilename
      Output to filename instead of STDOUT

  -v  Verbose compilation (currently gives a few compilation statistics).

  --  Force end of options

  -uPackname
      Force apparently unused subs from package Packname to be compiled.
      This allows programs to use eval "foo()" even when sub foo is never
      seen to be used at compile time. The down side is that any subs which
      really are never used also have code generated. This option is
      necessary, for example, if you have a signal handler foo which you
      initialise with "$SIG{BAR} = "foo"".  A better fix, though, is just to
      change it to "$SIG{BAR} = \!>foo". You can have multiple -u options. The
      compiler tries to figure out which packages may possibly have subs in
      which need compiling but the current version doesn't do it very well.
      In particular, it is confused by nested packages (i.e.  of the form
      "A::B") where package "A" does not contain any subs.

  -D  Debug options (concatenated or separate flags like "perl -D").

  -Do OPs, prints each OP as it's processed

  -Dc COPs, prints COPs as processed (incl. file & line num)

  -DA prints AV information on saving

  -DC prints CV information on saving

  -DM prints MAGIC information on saving

  -f  Force options/optimisations on or off one at a time. You can explicitly
      disable an option using -fno-option. All options default to disabled.

      -fcog
	  Copy-on-grow: PVs declared and initialised statically.

      -fsave-data
	  Save package::DATA filehandles ( only available with PerlIO ).

      -fppaddr
	  Optimize the initialization of op_ppaddr.

      -fwarn-sv
	  Optimize the initialization of cop_warnings.

      -fuse-script-name
	  Use the script name instead of the program name as $0.

      -fsave-sig-hash
	  Save compile-time modifications to the %SIG hash.

  -On Optimisation level (n = 0, 1, 2, ...). -O means -O1.

      -O0 Disable all optimizations.

      -O1 Enable -fcog.

      -O2 Enable -fppaddr, -fwarn-sv.

  -llimit
      Some C compilers impose an arbitrary limit on the length of string
      constants (e.g. 2048 characters for Microsoft Visual C++).  The -llimit
      options tells the C backend not to generate string literals exceeding
      that limit.


EXAMPLES

      perl -MO=C,-ofoo.c foo.pl
      perl cc_harness -o foo foo.c

  Note that "cc_harness" lives in the "B" subdirectory of your perl library
  directory. The utility called "perlcc" may also be used to help make use of
  this compiler.

      perl -MO=C,-v,-DcA,-l2048 bar.pl > /dev/null


BUGS

  Plenty. Current status: experimental.


AUTHOR

  Malcolm Beattie, "mbeattie@sable.ox.ac.uk"

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