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 optimisations on or off one at a time.

-fcog

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

-fno-cog

No copy-on-grow.

-On

Optimisation level (n = 0, 1, 2, ...). -O means -O1. Currently, -O1 and higher set -fcog.

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 bar.pl > /dev/null

BUGS

Plenty. Current status: experimental.

AUTHOR

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

DISCLAIMER

We are painfully aware that these documents may contain incorrect links and misformatted HTML. Such bugs lie in the automatic translation process that automatically created the hundreds and hundreds of separate documents that you find here. Please do not report link or formatting bugs, because we cannot fix per-document problems. The only bug reports that will help us are those that supply working patches to the installhtml or pod2html programs, or to the Pod::HTML module itself, for which I and the entire Perl community will shower you with thanks and praises.

If rather than formatting bugs, you encounter substantive content errors in these documents, such as mistakes in the explanations or code, please use the perlbug utility included with the Perl distribution.

--Tom Christiansen, Perl Documentation Compiler and Editor

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