[Bug libstdc++/108046] New: The dot in the floating-point alternative form has wrong position

[Bug libstdc++/108046] New: The dot in the floating-point alternative form has wrong position

[hewillk at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108046

            Bug ID: 108046
           Summary: The dot in the floating-point alternative form has
                    wrong position
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hewillk at gmail dot com
  Target Milestone: ---

#include <format>
#include <iostream>

int main() {
  std::cout << std::format("{:#.0}\n", 10.);
  std::cout << std::format("{:#.1}\n", 10.);
  std::cout << std::format("{:#.0g}\n", 10.);
}

libstdc++ gives:

1e+01.
1e+01.
1e+01

But they should all be "1.e+01"

https://godbolt.org/z/Y41ve6E7W

[Bug libstdc++/108046] The dot in the floating-point alternative form has wrong position

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108046

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |13.0
     Ever confirmed|0                           |1
           Assignee|unassigned at gcc dot gnu.org      |redi at gcc dot gnu.org
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2022-12-10

[Bug libstdc++/108046] The dot in the floating-point alternative form has wrong position

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108046

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|13.0                        |13.2

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 13.1 is being released, retargeting bugs to GCC 13.2.

[Bug libstdc++/108046] The dot in the floating-point alternative form has wrong position

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108046

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|13.2                        |13.3

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 13.2 is being released, retargeting bugs to GCC 13.3.

[Bug libstdc++/108046] The dot in the floating-point alternative form has wrong position

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108046

--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jonathan Wakely <redi@gcc.gnu.org>:

https://gcc.gnu.org/g:50bc490c090cc95175e6068ed7438788d7fd7040

commit r14-2825-g50bc490c090cc95175e6068ed7438788d7fd7040
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Thu Jul 27 14:07:09 2023 +0100

    libstdc++: Fix std::format alternate form for floating-point [PR108046]

    A decimal point was being added to the end of the string for {:#.0}
    because the __expc character was not being set, for the _Pres_none
    presentation type, so __s.find(__expc) didn't the 'e' in "1e+01" and so
    we created "1e+01." by appending the radix char to the end.

    This can be fixed by ensuring that __expc='e' is set for the _Pres_none
    case. I realized we can also set __expc='P' and __expc='E' when needed,
    to save a call to std::toupper later.

    For the {:#.0g} format, __expc='e' was being set and so the 'e' was
    found in "1e+10" but then __z = __prec - __sigfigs would wraparound to
    SIZE_MAX. That meant we would decide not to add a radix char because the
    number of extra characters to insert would be 1+SIZE_MAX i.e. zero.

    This can be fixed by using __z == 0 when __prec == 0.

    libstdc++-v3/ChangeLog:

            PR libstdc++/108046
            * include/std/format (__formatter_fp::format): Ensure __expc is
            always set for all presentation types. Set __z correctly for
            zero precision.
            * testsuite/std/format/functions/format.cc: Check problem cases.

[Bug libstdc++/108046] The dot in the floating-point alternative form has wrong position

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108046

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|2022-12-10 00:00:00         |2023-07-27

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Fixed on trunk so far.

[Bug libstdc++/108046] The dot in the floating-point alternative form has wrong position

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108046

--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-13 branch has been updated by Jonathan Wakely
<redi@gcc.gnu.org>:

https://gcc.gnu.org/g:da1ba03245c212ef1ba100e7806588802f3ad46f

commit r13-7914-gda1ba03245c212ef1ba100e7806588802f3ad46f
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Thu Jul 27 14:07:09 2023 +0100

    libstdc++: Fix std::format alternate form for floating-point [PR108046]

    A decimal point was being added to the end of the string for {:#.0}
    because the __expc character was not being set, for the _Pres_none
    presentation type, so __s.find(__expc) didn't the 'e' in "1e+01" and so
    we created "1e+01." by appending the radix char to the end.

    This can be fixed by ensuring that __expc='e' is set for the _Pres_none
    case. I realized we can also set __expc='P' and __expc='E' when needed,
    to save a call to std::toupper later.

    For the {:#.0g} format, __expc='e' was being set and so the 'e' was
    found in "1e+10" but then __z = __prec - __sigfigs would wraparound to
    SIZE_MAX. That meant we would decide not to add a radix char because the
    number of extra characters to insert would be 1+SIZE_MAX i.e. zero.

    This can be fixed by using __z == 0 when __prec == 0.

    libstdc++-v3/ChangeLog:

            PR libstdc++/108046
            * include/std/format (__formatter_fp::format): Ensure __expc is
            always set for all presentation types. Set __z correctly for
            zero precision.
            * testsuite/std/format/functions/format.cc: Check problem cases.

    (cherry picked from commit 50bc490c090cc95175e6068ed7438788d7fd7040)

[Bug libstdc++/108046] The dot in the floating-point alternative form has wrong position

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108046

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|ASSIGNED                    |RESOLVED

--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Fixed for 13.3, thanks for the report.