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General HydroStatics
Ship Stability Software |
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Command of the Week
(New or interesting aspects of GHS that you may not know about) |
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WRITE (LINE) vs. MESSAGE (REPORT)
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Both WRITE (LINE) and ME (REPORT) are useful for writing text files.
You can use either one or both to output one or more lines of text to a file.
For example: |
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ME (REPORT) COW166.TXT ME "leaves the file open, which means a line of text is ME "appended to the file by any subsequent ME command until ME (REPORT) OFF ME (REPORT) COW166.TXT /APPEND ME "closes the file. ME (REPORT) OFF WRITE (LINE) COW166.TXT \does not leave the file open: it adds one or more \lines of text and then closes the file. MESSAGE (REPORT) COW166.TXT /APPEND ME "can be used that way too: use ME (REPORT) OFF WRITE (LINE) COW166.TXT \before doing anything else. ME (REPORT) COW166.TXT /APPEND ME "But the file can be left open, which is a ME "convenience and a limitation. ME "The convenience is obvious. The limitation ME "is that when this file is open ME "you cannot use the MESSAGE command for ME "anything else, which is obvious too, ME "but knowing whether ME (REPORT) filename ME "is in effect or not may not be obvious. IF FEXIST COW166A.TXT THEN ERASE COW166A.TXT WRITE (LINE) COW166A.TXT \Note: this WRITE (LINE) method never leaves \the file open, and it always appends to the file. \It's simple and straightforward and quite safe. ME "So would good practice be to issue ME "ME (REPORT) OFF just before the ME "ME (REPORT) filename command? ME "Whether it is a good thing or not, GHS does it ME "for you. Any file left open by ME "ME (REPORT) filename is closed automatically ME "if not closed by ME (REPORT) OFF before the ME "next ME (REPORT) filename. That's fine, but it's ME "possible that the code that had left the file ME "open is assuming that it is still open. WRITE (LINE) COW166A.TXT \allows two files to be open simultaneously. \This is the bottom line. ME (REPORT) OFF COPY COW166A.TXT COW166.TXT /APPEND |
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Questions, comments, or requests?
Contact Creative Systems, Inc. USA phone: 360-385-6212 Fax: 360-385-6213 Office hours: 7:00 am - 4:00 pm Pacific Time, Monday - Friday Mailing address: PO Box 1910 Port Townsend, WA 98368 USA Click here for an index to this and previous COWs |