B::C
Section: Perl Programmers Reference Guide (3)
Updated: perl 5.005, patch 02
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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
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- OPTIONS
-
- EXAMPLES
-
- BUGS
-
- AUTHOR
-
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