To: J3                                                     J3/26-172
From: /HPC
Subject: Responses to UTIs for interoperability with C (003, 004, 005)
Date: 2026-June-12

Reference: 26-007r1 25-203r1

In 26-007r1, the Editor identified three unresolved technical
issues (UTIs) associated with improvements to interoperability with C.
The HPC subgroup makes the following recommendations:

========

UTI 003 "Redundant synonyms are unnecessary and unhelpful."

    Adding all those *_COMPLEX named constants just confuses people who
    haven't completely understood that type complex kind numbers are by
    definition identical to the real kind numbers for their parts. It
    bloats the language, the module, and the user programs that we
    thereby encourage to use these names. It's too late to get rid of
    the old ones, but we should not continue to add more useless and
    unnecessarily verbose names.

HPC subgroup agrees with the Editor. The following edit reverts the
relevant changes from paper 25-203r1:

----

[604:14-18] Replace the sentence

    The values of C_FLOAT_COMPLEX, C_DOUBLE_COMPLEX,
    C_LONG_DOUBLE_COMPLEX, C_FLOAT16_COMPLEX, C_FLOAT32_COMPLEX,
    C_FLOAT64_COMPLEX, C_FLOAT128_COMPLEX, C_FLOAT32X_COMPLEX,
    C_FLOAT64X_COMPLEX, and C_FLOAT128X_COMPLEX shall be the same as
    those of C_FLOAT, C_DOUBLE, C_LONG_DOUBLE, C_FLOAT16,C_FLOAT32,
    C_FLOAT64, C_FLOAT128, C_FLOAT32X, C_FLOAT64X, and C_FLOAT128X,
    respectively.

with the sentence

    The values of C_FLOAT_COMPLEX, C_DOUBLE_COMPLEX, and
    C_LONG_DOUBLE_COMPLEX, shall be the same as those of C_FLOAT,
    C_DOUBLE, and C_LONG_DOUBLE, respectively.

----

[613-614:table 19.2] Remove the following rows from the COMPLEX section
of the table:

      +---------------------+---------------------+
      | C_FLOAT16_COMPLEX   |   _Float16 _Complex |
      | C_FLOAT32_COMPLEX   |   _Float32 _Complex |
      | C_FLOAT64_COMPLEX   |   _Float64 _Complex |
      | C_FLOAT128_COMPLEX  |  _Float128 _Complex |
      | C_FLOAT32X_COMPLEX  |  _Float32x _Complex |
      | C_FLOAT64X_COMPLEX  |  _Float64x _Complex |
      | C_FLOAT128X_COMPLEX | _Float128x _Complex |
      +---------------------+---------------------+

Delete UTI 003.

========

UTI 004 "Potential contradictions are unhelpful."

    Did not insert "If the companion processor defines the C
    preprocessor macros __STDC_IEC_60559_BFP__ and
    __STDC_IEC_60559_TYPES__, the values of C_FLOAT32 and C_FLOAT64
    shall be the same as those of C_FLOAT and C_DOUBLE, respectively."

HPC subgroup agrees with the Editor. Delete UTI 004.

========

UTI 005 "What is the point of adding a synonym?"

    There is no good reason for having two names for the same C type.
    ...
    We cannot get rid of CFI_type_Bool without incompatibility, so we
    need to keep that, but there seems to be little to gain by adding
    CFI_type_bool as a synonym.

HPC subgroup agrees with the Editor. Delete UTI 005.

==END==