Initial commit of OpenSPARC T2 design and verification files.

[OpenSPARC-T2-DV] / tools / perl-5.8.0 / man / man3 / Cwd.3

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.\" ========================================================================
.\"
.IX Title "Cwd 3"
.TH Cwd 3 "2002-06-01" "perl v5.8.0" "Perl Programmers Reference Guide"
.SH "NAME"
Cwd \- get pathname of current working directory
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 2
\&    use Cwd;
\&    my $dir = getcwd;
.Ve
.PP
.Vb 2
\&    use Cwd 'abs_path';
\&    my $abs_path = abs_path($file);
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
This module provides functions for determining the pathname of the
current working directory.  It is recommended that getcwd (or another
*\fIcwd()\fR function) be used in \fIall\fR code to ensure portability.
.PP
By default, it exports the functions \fIcwd()\fR, \fIgetcwd()\fR, \fIfastcwd()\fR, and
\&\fIfastgetcwd()\fR into the caller's namespace.  
.Sh "getcwd and friends"
.IX Subsection "getcwd and friends"
Each of these functions are called without arguments and return the
absolute path of the current working directory.
.IP "getcwd" 4
.IX Item "getcwd"
.Vb 1
\&    my $cwd = getcwd();
.Ve
.Sp
Returns the current working directory.
.Sp
Re-implements the \fIgetcwd\fR\|(3) (or \fIgetwd\fR\|(3)) functions in Perl.
.Sp
Taint\-safe.
.IP "cwd" 4
.IX Item "cwd"
.Vb 1
\&    my $cwd = cwd();
.Ve
.Sp
The \fIcwd()\fR is the most natural form for the current architecture. For
most systems it is identical to `pwd` (but without the trailing line
terminator).
.Sp
Taint\-safe.
.IP "fastcwd" 4
.IX Item "fastcwd"
.Vb 1
\&    my $cwd = fastcwd();
.Ve
.Sp
A more dangerous version of \fIgetcwd()\fR, but potentially faster.
.Sp
It might conceivably \fIchdir()\fR you out of a directory that it can't
\&\fIchdir()\fR you back into.  If fastcwd encounters a problem it will return
undef but will probably leave you in a different directory.  For a
measure of extra security, if everything appears to have worked, the
\&\fIfastcwd()\fR function will check that it leaves you in the same directory
that it started in. If it has changed it will \f(CW\*(C`die\*(C'\fR with the message
\&\*(L"Unstable directory path, current directory changed
unexpectedly\*(R". That should never happen.
.IP "fastgetcwd" 4
.IX Item "fastgetcwd"
.Vb 1
\&  my $cwd = fastgetcwd();
.Ve
.Sp
The \fIfastgetcwd()\fR function is provided as a synonym for \fIcwd()\fR.
.Sh "abs_path and friends"
.IX Subsection "abs_path and friends"
These functions are exported only on request.  They each take a single
argument and return the absolute pathname for it.
.IP "abs_path" 4
.IX Item "abs_path"
.Vb 1
\&  my $abs_path = abs_path($file);
.Ve
.Sp
Uses the same algorithm as \fIgetcwd()\fR.  Symbolic links and relative-path
components (\*(L".\*(R" and \*(L"..\*(R") are resolved to return the canonical
pathname, just like \fIrealpath\fR\|(3).
.Sp
Taint\-safe.
.IP "realpath" 4
.IX Item "realpath"
.Vb 1
\&  my $abs_path = realpath($file);
.Ve
.Sp
A synonym for \fIabs_path()\fR.
.Sp
Taint\-safe.
.IP "fast_abs_path" 4
.IX Item "fast_abs_path"
.Vb 1
\&  my $abs_path = fast_abs_path($file);
.Ve
.Sp
A more dangerous, but potentially faster version of abs_path.
.Sp
This function is \fBNot\fR taint-safe : you can't use it in programs
that work under taint mode.
.Sh "$ENV{\s-1PWD\s0}"
.IX Subsection "$ENV{PWD}"
If you ask to override your \fIchdir()\fR built-in function, 
.PP
.Vb 1
\&  use Cwd qw(chdir);
.Ve
.PP
then your \s-1PWD\s0 environment variable will be kept up to date.  Note that
it will only be kept up to date if all packages which use chdir import
it from Cwd.
.SH "NOTES"
.IX Header "NOTES"
.IP "\(bu" 4
Since the path seperators are different on some operating systems ('/'
on Unix, ':' on MacPerl, etc...) we recommend you use the File::Spec
modules wherever portability is a concern.
.IP "\(bu" 4
Actually, on Mac \s-1OS\s0, the \f(CW\*(C`getcwd()\*(C'\fR, \f(CW\*(C`fastgetcwd()\*(C'\fR and \f(CW\*(C`fastcwd()\*(C'\fR
functions  are all aliases for the \f(CW\*(C`cwd()\*(C'\fR function, which, on Mac \s-1OS\s0,
calls `pwd`. Likewise, the \f(CW\*(C`abs_path()\*(C'\fR function is an alias for
\&\f(CW\*(C`fast_abs_path()\*(C'\fR.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
File::chdir