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From: David Blaikie <dblaikie@gmail.com>
Date: Sun, 13 Jun 2021 08:43:49 -0700
Message-ID: <CAENS6Es6NX-2WJbNBSEj8UG1OYEsvG9ueRxQw7KxUnA6qtZkQA@mail.gmail.com>
Subject: Re: Why does the prettyprint of std::tuple start with [1]?
To: paul@mad-scientist.net
Cc: gdb <gdb@sourceware.org>
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Likely it does, yeah.

Probably a bug in libstdc++'s pretty printer:

https://github.com/gcc-mirror/gcc/blob/8a7d54b1e10b8f4fba1358260ed2e7056ed23cbd/libstdc%2B%2B-v3/python/libstdcxx/v6/printers.py#L528

https://github.com/gcc-mirror/gcc/blob/8a7d54b1e10b8f4fba1358260ed2e7056ed23cbd/libstdc%2B%2B-v3/python/libstdcxx/v6/printers.py#L563

Something related to those bits of code.

On Sun, Jun 13, 2021 at 8:37 AM Paul Smith <paul@mad-scientist.net> wrote:

> On Sun, 2021-06-13 at 09:49 -0400, Paul Smith wrote:
> > Am I the only one to be confused by the fact that the pretty-printer
> > for std::tuple values starts indexing at 1 instead of 0?
> >
> > (gdb) p info
> > $1 = (const std::tuple<TestType, DataType> &) @0x7fffffffd550: {
> >   param = std::tuple containing = {
> >     [1] = TestType::OneTest,
> >     [2] = DataType::SomeData
> >   },
> >   index = 2
> > }
> >
> > Why aren't the indexes on the left numbered [0] and [1],
> > corresponding
> > to the values used with std::get(), instead of [1] and [2]?
>
> Hm, maybe this belongs on the GCC mailing list instead of here.
>
>