MirOS Manual: B::C(3p)


ext::B::B::C(3p)Perl Programmers Reference Guide ext::B::B::C(3p)

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 fig-
         ure 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 pack-
         ages (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

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     -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 stati-
             cally.

         -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

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     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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