43 lines
1.7 KiB
Plaintext
43 lines
1.7 KiB
Plaintext
This file describes the more significant of the changes
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made by Silicon Graphics, during its port of DIFF 1.15.
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The file "Changes.gnu-sgi.diff.out" contains a diff
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(using -uw options) output between the original source
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and the final SGI port, for each *.c and *.h file.
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As part of the port, SGI:
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1) optimized performance in the case that the files
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being diff'd don't fit comfortably in main memory.
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In this large file case, if no GNU specific options
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are specified, and if /usr/bin/odiff is present,
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then odiff is automatically invoked, since it is
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much faster on huge files. This port of GNU diff
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is typically faster on files that fit in main memory,
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thanks in part to its use of mmap, and to a quite
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different algorithm optimized for this case.
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2) optimized performance in the case that the two
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files being diff'd are identical. Consequently
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diff of two identical files is actually quite
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a bit faster than "cmp" of the same two files.
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3) Dropped support for GNU's +longoptions, in part
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since they are changing the syntax to --longoption
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in future GNU diff releases, and it didn't make
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sense to support the +longoption form for just
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this single release from SGI.
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4) added the local SGI "diff -x" option, for excluding
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subtrees on a recursive diff.
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5) determine if files are binary (which by default
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can result in the message: Binary files %s and %s differ)
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by checking for NUL bytes in the first BUFSIZ (8k)
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bytes. This NUL check is consistent with SVR4
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and with previous versions of diff on SGI systems.
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The GNU source for diff 1.15 checked instead
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for characters that were not in the ISO 8859 set.
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Silicon Graphics
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Dec 29, 1992
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