[gcc r10-8918] libstdc++: Fix documentation for return values of copy algos

[Jonathan Wakely]

https://gcc.gnu.org/g:0fa9ec49e372e148f58ffe0f360fd3f3d20cd31d

commit r10-8918-g0fa9ec49e372e148f58ffe0f360fd3f3d20cd31d
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Mon Oct 12 18:14:01 2020 +0100

    libstdc++: Fix documentation for return values of copy algos
    
    The doxygen comments for these algos all incorrectly claim to use
    (first - last) as the difference from the start of the output range to
    the return value. As reported on the mailing list by Johannes Choo, it
    should be (last - first).
    
    libstdc++-v3/ChangeLog:
    
            * include/bits/stl_algobase.h (copy, move, copy_backward)
            (move_backward): Fix documentation for returned iterator.
    
    (cherry picked from commit ae3967caffea9c9b9f0f9dfe42a4f59e715e1a61)

Diff:
---
 libstdc++-v3/include/bits/stl_algobase.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/libstdc++-v3/include/bits/stl_algobase.h b/libstdc++-v3/include/bits/stl_algobase.h
index d41a7df57fb..e397ccf64c3 100644
--- a/libstdc++-v3/include/bits/stl_algobase.h
+++ b/libstdc++-v3/include/bits/stl_algobase.h
@@ -543,7 +543,7 @@ _GLIBCXX_END_NAMESPACE_CONTAINER
    *  @param  __first  An input iterator.
    *  @param  __last   An input iterator.
    *  @param  __result An output iterator.
-   *  @return   result + (first - last)
+   *  @return   result + (last - first)
    *
    *  This inline function will boil down to a call to @c memmove whenever
    *  possible.  Failing that, if random access iterators are passed, then the
@@ -576,7 +576,7 @@ _GLIBCXX_END_NAMESPACE_CONTAINER
    *  @param  __first  An input iterator.
    *  @param  __last   An input iterator.
    *  @param  __result An output iterator.
-   *  @return   result + (first - last)
+   *  @return   result + (last - first)
    *
    *  This inline function will boil down to a call to @c memmove whenever
    *  possible.  Failing that, if random access iterators are passed, then the
@@ -779,7 +779,7 @@ _GLIBCXX_END_NAMESPACE_CONTAINER
    *  @param  __first  A bidirectional iterator.
    *  @param  __last   A bidirectional iterator.
    *  @param  __result A bidirectional iterator.
-   *  @return   result - (first - last)
+   *  @return   result - (last - first)
    *
    *  The function has the same effect as copy, but starts at the end of the
    *  range and works its way to the start, returning the start of the result.
@@ -815,7 +815,7 @@ _GLIBCXX_END_NAMESPACE_CONTAINER
    *  @param  __first  A bidirectional iterator.
    *  @param  __last   A bidirectional iterator.
    *  @param  __result A bidirectional iterator.
-   *  @return   result - (first - last)
+   *  @return   result - (last - first)
    *
    *  The function has the same effect as move, but starts at the end of the
    *  range and works its way to the start, returning the start of the result.