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| -rw-r--r-- | src/sort.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/src/sort.c b/src/sort.c index 7ac809049..8c92b0855 100644 --- a/src/sort.c +++ b/src/sort.c @@ -1881,7 +1881,17 @@ sortlines_temp (struct line *lines, size_t nlines, struct line *temp) } /* Return the index of the first of NFILES FILES that is the same file - as OUTFILE. If none can be the same, return NFILES. */ + as OUTFILE. If none can be the same, return NFILES. + + This test ensures that an otherwise-erroneous use like + "sort -m -o FILE ... FILE ..." copies FILE before writing to it. + It's not clear that POSIX requires this nicety. + Detect common error cases, but don't try to catch obscure cases like + "cat ... FILE ... | sort -m -o FILE" + where traditional "sort" doesn't copy the input and where + people should know that they're getting into trouble anyway. + Catching these obscure cases would slow down performance in + common cases. */ static int first_same_file (char * const *files, int nfiles, char const *outfile) |