(tye)Re: Platform Differences

I'll disagree with some of the points provided so far.

Use binmode on binary files regardless of platform. The fact that it might be a no-op on some platforms doesn't make it a portability problem. It is just not using it when you should that is a portability problem.
Avoid signal handlers in Perl. Work has begun on making them reliable, but it isn't available yet.
Newlines only cause problems when files are copied between platforms improperly. This again isn't a problem with writing portable scripts. It can be a challenge when writing scripts that tolerate inappropriate newlines no matter what platform they run on.

My suggestions on porting are more along the lines of "use modules" first, Perl second, and avoid everything else. So use IPC::Open3 not fork. Use File::Copy and mkdir not system. Use readdir not qx.

- tye (but my friends call me "Tye")

Comment on (tye)Re: Platform Differences

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Re: (tye)Re: Platform Differences by arhuman (Vicar) on Aug 07, 2001 at 16:30 UTC
Newlines cause other problems than just cross-platform transfert. As read in perlport : Due to the ``text'' mode translation, DOSish perls have limitations of using seek and tell when a file is being accessed in ``text'' mode. Specifically, if you stick to seek-ing to locations you got from tell (and no others), you are usually free to use seek and tell even in ``text'' mode. In general, using seek or tell or other file operations that count bytes instead of characters, without considering the length of \n, may be non-portable. If you use binmode on a file, however, you can usually use seek and tell with arbitrary values quite safely. "Only Bad Coders Code Badly In Perl" (OBC2BIP)	[reply]
(tye)Re2: Platform Differences by tye (Sage) on Aug 07, 2001 at 21:33 UTC
For what it's worth, I don't consider this a problem with newlines either. That is just a standard limitation of C's seek() for non-byte-stream files. I never use seek to skip byte offsets. MacOS has a different newline but has byte-stream files. Other operating systems don't even have newlines and don't have byte-stream files and so tell doesn't give you a byte offset anyway (if gives you a record number and an offset within that, for example). - tye (but my friends call me "Tye")	[reply]