From: Keith Burton (kb_at_[hidden])
Date: 2002-09-19 02:49:10
I believe that the issues mentioned below can be resolved by making all
paths absolute when constructed.
the path constructors is defined as :
path( const char * name ) // relative to current
path( const char * name, const path & relative_to )
path( "foo", "/bar" )
// gives absolute name on windows by using the drive of the current
directory when the path "/bar" is constructed
Obviously this style can be applied to an absolute function by defining
absolute( "foo", "/bar" ) as being evaluated as absolute(
"foo", absolute( "/bar" ) )
absolute( "" ) gives current directory
[mailto:boost-bounces_at_[hidden]] On Behalf Of Beman Dawes
Sent: 19 September 2002 00:01
Subject: Re: [boost] Filesystem Library: Formal Review
I think there are actually three valid choices for supplying absolute
(1) The current directory (and drive, volume or other system_specific
(2) An explicitly supplied path (via a second argument.)
(3) can be coded explicitly as the second argument with the interface
having to make any special provision, but we might want to make it the
Another thing that has to be nailed down is what happens with various
boundary conditions. For example:
absolute( "foo", "bar" ) // Oops, 2nd arg isn't absolute
absolute( "foo", "c:" ) // Oops, 2nd arg isn't absolute on Windows
absolute( "foo", "/bar" )// Oops, 2nd arg isn't absolute on Windows
absolute( "" ) // What does this return?
The third one is particularly tricky because it is perfectly valid for
POSIX but not for multi-rooted systems like Windows.
Also, note that the 2nd and 3rd are system specific, but I don't think
should be implied.
Basically, it is necessary to allow system specific paths, and access to
the current directory, drive, etc. but they should always be slightly
(so people think twice about using them), and easy to find with
tools (so they can be found in source code). IOW, same rationale as the
new-style cast syntax.
A another question is that in effect we are making the current directory
available by calling absolute() with the right arguments, so would it be
better (in addition to absolute()) to just go ahead and add a
current_directory() function? Or a special path constructor?
And finally, how do we specify absolute() so that it still gives
behavior on an operating system which has no concept of current
Need to think about it a bit more.
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