manual: Clarify that abbreviations of long options are allowed

The man page and code comments clearly state that abbreviations of long
option names are recognized correctly as long as they are unique.
Document this fact in the glibc manual as well.

Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed-by: Florian Weimer <fweimer@redhat.com>
Reviewed-by: Andreas Schwab <schwab@linux-m68k.org>
(cherry picked from commit db1efe02c9f15affc3908d6ae73875b82898a489)

diff --git a/manual/getopt.texi b/manual/getopt.texi
index 5485fc46946631f73aea71d6da3fa77f8bbe2462..b4c0b15ac2060560783bda43b3ea9f66f0c930d9 100644 (file)
--- a/manual/getopt.texi
+++ b/manual/getopt.texi
@@ -250,7 +250,8 @@ option, and stores the option's argument (if it has one) in @code{optarg}.
 
 When @code{getopt_long} encounters a long option, it takes actions based
 on the @code{flag} and @code{val} fields of the definition of that
-option.
+option.  The option name may be abbreviated as long as the abbreviation is
+unique.
 
 If @code{flag} is a null pointer, then @code{getopt_long} returns the
 contents of @code{val} to indicate which option it found.  You should