Re: Cross platform compatability Part 1: Shells and Files

It irritates me, jepri, that you make a big deal of being cross platform compatible and offer alternatives for standard unix perlisms (with a few errors), and yet

you dont offer any way to actually detect which operating system we're running on and should be friendly enough to support
you dont cover any other operating system. its a little known fact that there are in fact more than two major operating systems out there. I'm curious to know what MacPerl does whether it converts file/path/ to file:path: or it actually needs colons.

I am actually currently involved in making cross-platform code and would be interested to know more about making things more windows and mac-friendly.

one last note:

open (FH, ">/temp/tempfile");
print FH $temporary_data;
[download]

I dont think I've ever worked on a *nix system that had a /temp directory. The Unix System Administration Handbook (3rd ed) doesnt mention it, either. You're looking for /tmp.

dep.

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Re: Re: Cross platform compatability Part 1: Shells and Files by chipmunk (Parson) on Jan 21, 2001 at 22:36 UTC
I'm curious to know what MacPerl does whether it converts file/path/ to file:path: or it actually needs colons. MacPerl does not convert 'file/path/' to 'file:path:'; one must actually use colons in the paths. Even trickier, however, is the way of specifying relative paths, by prepending the directory separator. On a Mac, ':mammal:dog' means the file dog in the directory mammal in the current working directory, whereas on Unix '/mammal/dog' means the file dog in the directory mammal in the root directory. On the other hand, the path 'animal:mammal:dog' on a Mac means the file dog in the directory mammal in the root directory of the volume animal. On Unix 'animal/mammal/dog' means the file 'dog' in the directory 'mammal' in the directory 'animal' in the current working directory. Here's a script that demonstrates this behavior in MacPerl: `use Cwd; print cwd(), "\n"; -e 'foo' or mkdir('foo', 0777) or die "Can't mkdir 'foo': $!\n"; open(FH, '>foo/bar') or warn "Can't open 'foo/bar': $!\n"; # creates a file named 'foo/bar' in cwd open(FH, '>foo:bar') or warn "Can't open 'foo:bar': $!\n"; # fails, unless you actually have a volume named 'foo' # in that case, creates a file named 'bar' on the volume 'foo' open(FH, '>:foo:bar') or warn "Can't open ':foo:bar': $!\n"; # creates a file named 'bar' in the directory 'foo' in the cwd` [download] Getting cross-platform file paths is not an easy problem. That's why the File::Spec module was created. (Except that all the documentation for the module is in File::Spec::Unix. You'll have to read it locally.)	[reply] [d/l]

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Re: Re: Cross platform compatability Part 1: Shells and Files
by chipmunk (Parson) on Jan 21, 2001 at 22:36 UTC

I'm curious to know what MacPerl does whether it converts file/path/ to file:path: or it actually needs colons.

MacPerl does not convert 'file/path/' to 'file:path:'; one must actually use colons in the paths.

Even trickier, however, is the way of specifying relative paths, by prepending the directory separator. On a Mac, ':mammal:dog' means the file dog in the directory mammal in the current working directory, whereas on Unix '/mammal/dog' means the file dog in the directory mammal in the root directory.

On the other hand, the path 'animal:mammal:dog' on a Mac means the file dog in the directory mammal in the root directory of the volume animal. On Unix 'animal/mammal/dog' means the file 'dog' in the directory 'mammal' in the directory 'animal' in the current working directory.

Here's a script that demonstrates this behavior in MacPerl:

  use Cwd;

  print cwd(), "\n";

  -e 'foo' or mkdir('foo', 0777) or die "Can't mkdir 'foo': $!\n";

  open(FH, '>foo/bar') or warn "Can't open 'foo/bar': $!\n";
    # creates a file named 'foo/bar' in cwd

  open(FH, '>foo:bar') or warn "Can't open 'foo:bar': $!\n";
    # fails, unless you actually have a volume named 'foo'
    # in that case, creates a file named 'bar' on the volume 'foo'

  open(FH, '>:foo:bar') or warn "Can't open ':foo:bar': $!\n";
    # creates a file named 'bar' in the directory 'foo' in the cwd
[download]

Getting cross-platform file paths is not an easy problem. That's why the File::Spec module was created. (Except that all the documentation for the module is in File::Spec::Unix. You'll have to read it locally.)

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[d/l]