p2c.man

把pascal程序转成C语言程序 把pascal程序转成C语言程序

.\" p2c  Copyright 1989, 1990, 1991, 1992, 1993 Free Software Foundation
.TH P2C 1 "local"
.SH NAME
p2c \- Pascal to C translator, version 1.21alpha-07.Dec.93
.SH SYNOPSIS
.B p2c
[ options ] [ file [ module ] ]
.SH DESCRIPTION
.I P2c
is a tool for translating Pascal programs into C.  The input consists
of a set of source files in any of the following Pascal dialects:
HP Pascal, Turbo/UCSD Pascal, DEC VAX Pascal, Oregon Software Pascal/2,
Macintosh Programmer's Workshop Pascal, Sun/Berkeley Pascal, Texas
Instruments Pascal, Apollo Domain Pascal.
Modula-2 syntax is also supported.  Output is a set of
.B .c
and
.B .h
files that comprise an equivalent program in any of several dialects
of C.  Output code may be kept machine- and dialect-independent, or
it may be targeted to a specific machine and compiler.  Most reasonable
Pascal programs are converted into fully functional C which will compile
and run with no further modifications, although
.I p2c
sometimes chooses to generate readable code at the expense of absolute
generality.  
.I P2c
endeavors to insert notes and warning messages into the output code
to point out areas which may require human intervention.  Output code
is arranged to be readable and efficient, and to make use of C idioms
wherever possible.  The main goal of the translation is to produce C
files which are pleasant and "natural" enough to be acceptable as the new
source files for a program.  In a pinch,
.I p2c
will also serve as an ad hoc Pascal compiler.  The
.BR p2cc (1)
script makes it easy to use
.I p2c
as a compiler.
.PP
Code generated by
.I p2c
normally does not assume characters are signed or unsigned.
Also, it assumes
.B int
is the same as either
.B short
or
.B long
but does not depend on which.  However, if
.B int
is not the same as
.BR long
it is best to use a modern C compiler which supports prototypes.
Generated code does not require an ANSI-compatible compiler
(unless ANSI-style code is requested), but it does use various
ANSI-standard library routines.
.PP
All generated code includes the file
.I <p2c/p2c.h>
which in turn includes
.I <stdio.h>
and various other common resources.  Also, many translated programs
will need to be linked with the run-time library, typically
.I -lp2c.
.PP
Given a file name,
.I p2c
reads from the specified file and outputs to a file with a
.B .c
suffix added or substituted.  For example,
.IP "" 5
p2c myfile.pas
.PP
reads from
.I myfile.pas
to produce the file
.I myfile.c.
The input file may contain a Pascal main program or a
single Pascal module (or "unit" in Turbo and UCSD Pascal nomenclature),
or it may just contain a number of procedures and declarations.
.I P2c
is designed to work for correct input programs.  That is, it will accept
partial programs but may occasionally core dump if the input refers to
undefined symbols.
.PP
If the input is a module, the translator will also produce a file
.IB module .h
containing a translation of the module's interface section.
The implementation section may be omitted in which case only the
.B .h
file will be interesting.  If the program or module has include files,
these may cause additional
.B .c
files to be generated depending on the value of the
.B ExpandIncludes
option (see below).
.PP
If no file name is given,
.I p2c
reads Pascal from the standard input and writes the resulting C to
standard output (though a
.B .h
file may still be produced).  If a file name and module name are given,
the file may include several modules (or units).  The specified module
is translated; any others are skipped.  The output files will be named
.IB module .c
and
.IB module .h .
.I P2c
never translates more than one module per run.
.PP
Before starting,
.I p2c
reads the file
.I --HOMEDIR--/p2crc
for a number of configuration parameters.  (The actual path used on your
system may vary.  The
.B \-i
option is a handy way to examine this file.)
If the P2CRC environment variable is set, it gives the name of a file
to read instead of the system file; this file can start with
.B Include %H/p2crc
to include the system file.  Next,
.I p2c
attempts to read the file
.I p2crc
in your directory for further configuration.  If this file does not
exist,
.I p2c
looks for
.I .p2crc
instead.
.SH OPTIONS
.TP
.BI \-o "\ cfile"
Use
.I cfile
in place of
.IB file .c
or
.IB module .c
as the primary output file.  A single dash (`\-o \-') says to write the
C code to the standard output.
.TP
.BI \-h "\ hfile"
Use
.I hfile
in place of
.IB module .h
as the output file for interface text.  This only has effect if the
input is an HP Pascal module or a Turbo Pascal unit.
.TP
.BI \-s "\ sfile"
Read interface text from
.I sfile
before beginning the translation.  This file typically contains one or
more modules, often with implementation sections omitted for speed, which
the program or module being translated will use.  (Typically the
.B ImportFrom
and
.B ImportDir
parameters in
.I p2crc
are set up to allow
.I p2c
to locate interface text without needing any
.B \-s
options.)  If there are several
.B \-s
options in the command, the
.I sfiles
are read from left to right.
.TP
.BI \-p n
Display progress of translation in the form of a line number/file name
display.  This is refreshed every
.I n
lines, 25 by default.
.TP
.BI \-c "\ rcfile"
Read local configuration commands from
.I rcfile
instead of
.I p2crc
or
.I .p2crc.
A dash (`\-c \-') in place of
.I rcfile
causes no local configuration file to be used.
.TP
.B \-v
("Vanilla.")  Do not read from the system configuration file
.I --HOMEDIR--/p2crc.
Since some of the parameters in this file are required, your local
configuration file must include those parameters instead.  This
also suppresses the file named by the P2CRC environment variable.
.TP
.BI \-H "\ homedir"
Use
.I homedir
instead of
.I --HOMEDIR--
as the
.I p2c
home directory.  The system
.I p2crc
file will be searched for in this directory. 
.TP
.BI \-I pattern
Add
.I pattern
to the
.B ImportDir
search list of places to find modules which are imported.  The pattern
should include a
.I %s
to represent the module name, and should evaluate to a potential file name
for that module's source code.  For example,
.B ../%s.pas
looks for
.IB modulename .pas
in the parent of the current directory.
.TP
.B \-i
This special option (which must be the only argument on the
command line if used) simply copies the system configuration
file
.I --HOMEDIR--/p2crc
to the standard output in its entirety.  (It may be used with
.BR \-H ,
but
.B \-i
is most useful precisely when you don't know the
location of the home directory.)
.TP
.B \-q
Quiet mode.  Suppresses output of status messages during translation.
.TP
.BI \-E n
Abort translation after
.I n
errors.  If
.I n
is omitted it defaults to zero, which means unlimited errors are allowed.
Use
.B -E1
to make
.I p2c
halt after the first error.
.TP
.B \-e
Echo the Pascal source into the output file, surrounded by #ifdefs.
This is the same as the
.B CopySource
parameter in the
.I p2crc
file.
.TP
.B \-a
Produce modern ANSI C.  This is a convenient override for the
.B AnsiC
parameter in the
.I p2crc
file.
.TP
.BI \-L "\ language"
Select input language name, such as VAX or TURBO.  This is a convenient
override for the
.B Language
parameter.
.TP
.B \-V
Verbose mode.  This causes
.I p2c
to generate an additional ".log" file with further details of the
translation, such as a list of warnings and notes including those
which are suppressed in the regular output.
.TP
.B \-comp
Compiler mode.  This switch tells
.I p2c
to use various configuration defaults that are more suitable for
use as a Pascal compiler rather than a translator.  It is the same
as specifying the following options in your
.I p2crc
file:
.IP
\ \ \ \ \ ElimDeadCode 0
.br
\ \ \ \ \ AnalyzeFlow 0
.br
\ \ \ \ \ MaxLineBreakTies 0
.br
\ \ \ \ \ FoldConstants 1
.br
\ \ \ \ \ FoldStrConstants 1
.br
\ \ \ \ \ OffsetForLoops 0
.br
\ \ \ \ \ StaticLinks 1
.br
\ \ \ \ \ BitwiseMod 0
.br
\ \ \ \ \ BitwiseDiv 0
.br
\ \ \ \ \ AssumeBits 0
.br
\ \ \ \ \ AssumeSigns 0
.br
\ \ \ \ \ FormatStrings 1
.br
\ \ \ \ \ StructFiles 1
.br
\ \ \ \ \ FullStrWrite 1
.IP
The
.I p2cc
script specifies this option when it runs
.I p2c
to compile a Pascal program.
.TP
.B \-local
Local settings.  This switch uses various configuration defaults
that are appropriate if the code generated by
.I p2c
is going to be compiled and run on the same machine that ran
.I p2c
itself.
.TP
.B \-check
Enable all error checking.  Normally, some error checks are off
by default, as described in the comments in the system
.I p2crc
file.
.TP
.B \-M0
Disable memory conservation.  This prevents
.I p2c
from freeing various data structures after translating each function,
in case this new conservation feature causes unforseen problems.
.TP
.B \-R
Regression testing mode.  Formats notes and warning messages in a way
that makes it easier to run
.IR diff (1)
on the output of
.I p2c.
.PP
.I P2c
also understands a few debugging options which may occasionally be
useful when tracking down translation problems.  The
.BI \-d n
option sets the "debug level" to
.I n,
a small integer which is normally zero.  Debugging output is
written into the regular output file along with the C code; the
higher your
.I n,
the more "wallpaper" you get.  Also,
.B \-t
prints debugging information at every Pascal token,
.BI \-B n
enables line-breaker debugging,
.BI \-C n
enables comment placement debugging, and
.BI \-F n
enables flow-analysis debugging.
.SH CHOICE OF SOURCE LANGUAGE
The
.B Language
configuration parameter or
.B \-L
command-line option tells
.I p2c
which Pascal dialect to expect in the input file.  Any language features
which do not overlap between dialects are supported all of the time.  The
.B Language
parameter is consulted when a syntax or usage is detected that has different
meanings in two different dialects, and also to determine default values
for various other translation parameters as described below.
.PP
The following language words are supported by
.I p2c.
Names are case-insensitive.
.TP 8
.B HP
HP Pascal.  This is the default language.  All features of HP Standard
Pascal, the Pascal Workstation version, are supported except as noted
in BUGS below.  Some features of MODCAL, HP's extended Pascal, are also
supported.  This is a superset of ISO standard Pascal, including
conformant arrays and procedural parameters.
.TP
.B HP-UX
HP Pascal, HP-UX version.  Almost identical to the "HP" dialect.
.TP
.B Turbo
Turbo Pascal 5.0 for the IBM PC.  Few conflicts with HP Pascal, so the
.B Language
parameter is not often needed for Turbo.  (Most important is that the Turbo
and HP dialects use 16 and 32 bit integers, respectively.)
.TP
.B UCSD
UCSD Pascal.  Similar to Turbo in many ways.
.TP
.B MPW
Macintosh Programmer's Workshop Pascal 2.0.  Should also do a pretty
good job for Lightspeed Pascal.  Object Pascal features are not supported,
nor is the fact that
.B char
variables are sometimes stored in 16 bits.
.TP
.B VAX
VAX/VMS Pascal version 3.5.  Most but not all language features supported.
This has not yet been tested on large programs.
.TP
.B Oregon
Oregon Software Pascal/2.  All features implemented.
.TP
.B Berk
Berkeley Pascal with Sun extensions.
.TP
.B TIP
Texas Instruments Pascal.
.TP
.B Apollo
Apollo Domain Pascal.
.TP
.B Modula