Don Simons wrote: > Thanks for the explanation. And of course I do know how PMX knows it's at > the end of the input, i.e., when there are no more lines of input to > read. > The thing I still don't understand is exactly this: if someone sends me a > file generated in their favorite OS, and I look at its binary image using > the PC command line program debug, is there any specific binary character > or characters that announces "this is the end of the file"?
No - the location of the end of data is indicated by the file's meta-data in the OS (i.e. it's the end of the file because you've read the x bytes listed in the directory tree as belonging to that file). That's the case right back to MS-DOS 1.00. There have been user-level conventions which involve using other markers (usually Control-Z) but that's either for compatibility with (very very) old and retired operating systems or for programs receiving input from standard input, rather than a file, where EOF is not a possible condition. > I think that in PC OS's the answer is "no", because after the last "0D 0A" > (CR LF), Note that a text file, certainly on Windows, is not even guaranteed to end with CRLF - Windows Notepad, for example, does not insert CRLF at the end of a text file unless you explicitly put a newline. Personally, my preference when reading text files (which eliminates all these headaches) is to use a small lex script, rather than any underlying language functions, so that you can treat the regular expression \r?\n as the end of file marker - that copes with mixed-mode files (where a text editor has managed to mix LF and CRLF endings) and is Windows/Unix neutral[*]. Equally, assuming there are no lexer generators for Fortran, then as long as you have support for opening files in binary mode, the state machine required is pretty simple. David [*] yes, I don't give the smallest damn about Mac OS 9 and earlier... ------------------------------- TeX-music@tug.org mailing list If you want to unsubscribe or look at the archives, go to http://tug.org/mailman/listinfo/tex-music
