From 94732c8a71d606796ea656593eb085fa0f43a04f Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Fri, 30 Jul 2004 23:24:03 +0000 Subject: [PATCH] Improve comment for first_same_file. --- src/sort.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/src/sort.c b/src/sort.c index 7ac809049c..8c92b0855f 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) -- 2.47.2