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[fix] #4565 When using MSVC to compile v12.0.0, many compilation warn…#4572

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vitaut merged 6 commits intofmtlib:masterfrom
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Oct 12, 2025
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[fix] #4565 When using MSVC to compile v12.0.0, many compilation warn…#4572
vitaut merged 6 commits intofmtlib:masterfrom
LiangHuDream:master

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@LiangHuDream LiangHuDream commented Oct 11, 2025

@esoft-com This warning occurs because on x86 Windows, size_t is a 32-bit unsigned integer, while unsigned __int64 is a 64-bit unsigned integer. Implicitly converting from unsigned __int64 to size_t can cause data loss, so MSVC emits warning C4244.
To resolve this, we should explicitly cast the value to size_t wherever the conversion happens, ideally at the point where the warning is triggered. thank you for checking the code

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LiangHuDream commented Oct 11, 2025

@vitaut
This warning occurs because on x86 Windows, size_t is a 32-bit unsigned integer, while unsigned __int64 is a 64-bit unsigned integer. Implicitly converting from unsigned __int64 to size_t can cause data loss, so MSVC emits warning C4244.
To resolve this, we should explicitly cast the value to size_t wherever the conversion happens, ideally at the point where the warning is triggered. thank you for checking the code

vitaut
vitaut requested changes Oct 11, 2025
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Thanks for the PR.

include/fmt/format.h Outdated
size += grouping.count_separators(exp);
return write_padded<Char, align::right>(
out, specs, to_unsigned(size), [&](iterator it) {
out, specs, to_unsigned(static_cast<size_t>(size)), [&](iterator it) {
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Let's remove to_unsigned since with the cast the argument is already unsigned.

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thank you for checking my code.

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Let's remove to_unsigned since with the cast the argument is already unsigned.

I modified it .

SteveRussell33
SteveRussell33 reviewed Oct 12, 2025
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include/fmt/format.h Outdated
size += grouping.count_separators(exp);
return write_padded<Char, align::right>(
out, specs, to_unsigned(size), [&](iterator it) {
out, specs, tatic_cast<size_t>(size), [&](iterator it) {
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Typo: should be static_cast

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@LiangHuDream LiangHuDream Oct 12, 2025 •
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Typo: should be static_cast

thank you, I modified it, and I run it successfully.

@vitaut vitaut merged commit 8eebb43 into fmtlib:master Oct 12, 2025
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vitaut commented Oct 12, 2025

Merged, thanks.

@vitaut vitaut mentioned this pull request Oct 12, 2025
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blizzard4591 added a commit to blizzard4591/fmt that referenced this pull request Oct 30, 2025
@blizzard4591
When using MSVC x32 to compile v12.0.0 or v12.1.0, conversions from _…
280a9fe 
…_int64 to a 32bit unsigned int trigger warnings.

This is a follow-up for PR fmtlib#4572.
blizzard4591 added a commit to blizzard4591/fmt that referenced this pull request Oct 30, 2025
@blizzard4591
When using MSVC x86 to compile v12.0.0 or v12.1.0, conversions from _…
5953419 
…_int64 to a 32bit unsigned int trigger warnings.

This is a follow-up for PR fmtlib#4572.
@blizzard4591 blizzard4591 mentioned this pull request Oct 30, 2025
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vitaut pushed a commit that referenced this pull request Nov 1, 2025
@blizzard4591
When using MSVC x86 to compile v12.0.0 or v12.1.0, conversions from _…
c3be070 
…_int64 to a 32bit unsigned int trigger warnings. (#4594)

This is a follow-up for PR #4572.
netbsd-srcmastr pushed a commit to NetBSD/pkgsrc that referenced this pull request Nov 2, 2025
@0-wiz-0
fmtlib: update to 12.1.0.
dde98b4 
# 12.1.0 - 2025-10-29

- Optimized `buffer::append`, resulting in up to ~16% improvement on spdlog
  benchmarks (fmtlib/fmt#4541). Thanks @fyrsta7.

- Worked around an ABI incompatibility in `std::locale_ref` between clang and
  gcc (fmtlib/fmt#4573).

- Made `std::variant` and `std::expected` formatters work with `format_as`
  (fmtlib/fmt#4574,
  fmtlib/fmt#4575). Thanks @phprus.

- Made `fmt::join<string_view>` work with C++ modules
  (fmtlib/fmt#4379,
  fmtlib/fmt#4577). Thanks @Arghnews.

- Exported `fmt::is_compiled_string` and `operator""_cf` from the module
  (fmtlib/fmt#4544). Thanks @CrackedMatter.

- Fixed a compatibility issue with C++ modules in clang
  (fmtlib/fmt#4548). Thanks @tsarn.

- Added support for cv-qualified types to the `std::optional` formatter
  (fmtlib/fmt#4561,
  fmtlib/fmt#4562). Thanks @OleksandrKvl.

- Added demangling support (used in exception and `std::type_info` formatters)
  for libc++ and clang-cl
  (fmtlib/fmt#4542,
  fmtlib/fmt#4560,
  fmtlib/fmt#4568,
  fmtlib/fmt#4571).
  Thanks @FatihBAKIR and @rohitsutreja.

- Switched to global `malloc`/`free` to enable allocator customization
  (fmtlib/fmt#4569,
  fmtlib/fmt#4570). Thanks @rohitsutreja.

- Made the `FMT_USE_CONSTEVAL` macro configurable by users
  (fmtlib/fmt#4546). Thanks @SnapperTT.

- Fixed compilation with locales disabled in the header-only mode
  (fmtlib/fmt#4550).

- Fixed compilation with clang 21 and `-std=c++20`
  (fmtlib/fmt#4552).

- Fixed a dynamic linking issue with clang-cl
  (fmtlib/fmt#4576,
  fmtlib/fmt#4584). Thanks @FatihBAKIR.

- Fixed a warning suppression leakage on gcc
  (fmtlib/fmt#4588). Thanks @ZedThree.

- Made more internal color APIs `constexpr`
  (fmtlib/fmt#4581). Thanks @ishani.

- Fixed compatibility with clang as a host compiler for NVCC
  (fmtlib/fmt#4564). Thanks @valgur.

- Fixed various warnings and lint issues
  (fmtlib/fmt#4565,
  fmtlib/fmt#4572,
  fmtlib/fmt#4557).
  Thanks @LiangHuDream and @teruyamato0731.

- Improved documentation
  (fmtlib/fmt#4549,
  fmtlib/fmt#4551,
  fmtlib/fmt#4566,
  fmtlib/fmt#4567,
  fmtlib/fmt#4578,).
  Thanks @teruyamato0731, @petersteneteg and @zimmerman-dev.
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