.\" ident	@(#)Path:man/Tmppath.3	3.2
.\"
.\" C++ Standard Components, Release 3.0.
.\"
.\" Copyright (c) 1991, 1992 AT&T and UNIX System Laboratories, Inc.
.\" Copyright (c) 1988, 1989, 1990 AT&T.  All Rights Reserved.
.\"
.\" THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF AT&T and UNIX System
.\" Laboratories, Inc.  The copyright notice above does not evidence
.\" any actual or intended publication of such source code.
.\" 
.tr ~"
.TH \f3Tmppath\fP \f3Path(3C++)\fP " "
.SH NAME
Tmppath \- Temporary path names
.SH "SYNOPSIS of Tmppath.h"
.Bf
#include <Path.h>

class Tmppath : public Path{
public:

//  Constructors

    Tmppath();
    Tmppath(const char* pfx,const char* ext = "");
    Tmppath(const Path& dir);
    Tmppath(const Path& dir,const char* pfx,
        const char* ext = "");

//  Implicit arguments

    static void use(const char* pfx);
    static void use(const Path& dir);
    static void use(const Path& dir,const char* pfx);
    static void use();
};
.Be
.SH DESCRIPTION
A Tmppath is just like a Path (see \f3Path(.)\f1), 
except it is initialized to a Path corresponding to a 
file which does not currently exist in the underlying file 
system.  
Tmppath should replace \f3mktemp(3)\f1, \f3tempnam(3)\f1 
and \f3tmpnam(3)\f1 in most C++ applications.
.SS "Constructors"
.IP "\f4Tmppath();\f1"
The dirname of the constructed path is the first
directory in the following list for which a Path corresponding
to a non-existent file can be constructed:
(1) the 
current 
value of the environment variable TMPDIR, if TMPDIR is set and is other than the empty string;
(2) ``/usr/tmp''; 
(3) ``/tmp''.
If a Path corresponding to a non-existent file cannot be constructed,
then Path(".") is constructed.

The dirname of the constructed Path is 
.I not 
checked for existence.
In particular, if TMPDIR does not exist in the underlying file system,
then TMPDIR will be used, and any attempt to open the resulting Tmppath 
will fail.
(Not checking the existence of the directory is done for efficiency
reasons when constructing many Tmppath's.)
.IP "\f4Tmppath(const char* pfx,const char* ext = ~~);\f1"
Same as above, except the basename of the constructed Path
begins with the prefix \f3pfx\f1, and 
ends with the suffix \f3ext\f1.
.IP "\f4Tmppath(const Path& dir);\f1"
.hS
.IP "\f4Tmppath(const Path& dir,const char* pfx,\f1"
.IC "\f4    const char* ext = ~~);\f1"
Same as the above two constructors respectively, 
except \f3dir\f1 is used as the dirname of the
constructed Path.  None of the other directories are tried.
.SS "Implicit arguments"
These functions make it possible to specify once and for all
a default directory and/or prefix to be used in all future Tmppath constructions.
Individual constructions are still free to override these defaults
by supplying explicit values for these arguments.
These functions should not be called during static initialization.
.IP "\f4static void use(const char* pfx);\f1"
\f3pfx\f1 is an implicit argument to all future constructions lacking that argument.
Future calls to other constructors have their original meanings.
.IP "\f4static void use(const Path& dir);\f1"
\f3dir\f1 is an implicit argument to all future constructions lacking that argument.
Future calls to other constructors have their original meanings.
.IP "\f4static void use(const Path& dir,const char* pfx);\f1"
\f3dir\f1 and \f3pfx\f1 are implicit arguments to all future constructions lacking 
either of those arguments.
.IP "\f4static void use();\f1"
Future calls to constructors have their original meanings.
.SH WARNINGS
It is completely up to the programmer to prevent the
race between constructing a Tmppath and opening it for writing.
As usual, the easiest way of guaranteeing no race
is to use \f3tmpfile(3)\f1.
.PP
An attempt to open a Tmppath can fail either if 
the program has lost the construct/open race, 
or the directory corresponding to the dirname of the
Tmppath does not exist in the underlying file system.
.PP
The Tmppath constructor is subtly overloaded.  Beware.
.SH SEE ALSO
.Bf
\f3mktemp(3)\fP
\f3tempnam(3)\fP
\f3tmpfile(3)\fP
\f3tmpnam(3)\fP
\f3Path(.)\fP
\f3Search_path(.)\fP
.Be