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Fix -Wsign-compare and -Wundef warnings from clang on Windows #330

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Merged
merged 1 commit into from
Nov 26, 2025
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Fix -Wsign-compare and -Wundef warnings from clang on Windows #330

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4 changes: 2 additions & 2 deletions src/time_zone_format.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -39,7 +39,7 @@
#include <limits>
#include <string>
#include <vector>
#if !HAS_STRPTIME
#if !defined(HAS_STRPTIME)
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@devbww devbww Nov 26, 2025

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#if !defined(HAS_STRPTIME) is not the same as #if !HAS_STRPTIME when HAS_STRPTIME=0, which is intended to be a valid way to say "I don't have strptime()".

I see that we have #if defined(HAS_STRPTIME) && HAS_STRPTIME in another place (presumably to workaround the same warning), so I suggest we rework these new changes with the negation of that.

[All that said, I'm not a fan of -Wundef, but I guess that's a lost argument.]

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@derekmauro derekmauro Nov 26, 2025

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#331 addresses this comment.

#include <iomanip>
#include <sstream>
#endif
Expand All @@ -52,7 +52,7 @@ namespace detail {

namespace {

#if !HAS_STRPTIME
#if !defined(HAS_STRPTIME)
// Build a strptime() using C++11's std::get_time().
char* strptime(const char* s, const char* fmt, std::tm* tm) {
std::istringstream input(s);
Expand Down
23 changes: 11 additions & 12 deletions src/time_zone_name_win.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@

#include <algorithm>
#include <atomic>
#include <cstddef>
#include <cstdint>
#include <limits>
#include <string>
Expand Down Expand Up @@ -129,15 +130,14 @@ std::string Utf16ToUtf8(const wchar_t* ptr, size_t size) {
}
const int chars_len = static_cast<int>(size);
std::string result;
std::int32_t len = std::max<std::int32_t>(
static_cast<std::int32_t>(std::min<size_t>(
result.capacity(), std::numeric_limits<std::int32_t>::max())),
1);
std::size_t len = std::max<std::size_t>(
std::min<size_t>(result.capacity(), std::numeric_limits<int>::max()), 1);
do {
result.resize(len);
// TODO: Switch to std::string::data() when we require C++17 or higher.
len = ::WideCharToMultiByte(CP_UTF8, WC_ERR_INVALID_CHARS, ptr, chars_len,
&result[0], len, nullptr, nullptr);
len = static_cast<std::size_t>(::WideCharToMultiByte(
CP_UTF8, WC_ERR_INVALID_CHARS, ptr, chars_len, &result[0],
static_cast<int>(len), nullptr, nullptr));
} while (len > result.size());
result.resize(len);
return result;
Expand All @@ -157,15 +157,14 @@ std::string GetWindowsLocalTimeZone() {
}

std::wstring result;
std::int32_t len = std::max<std::int32_t>(
static_cast<std::int32_t>(std::min<size_t>(
result.capacity(), std::numeric_limits<std::int32_t>::max())),
1);
std::size_t len = std::max<std::size_t>(
std::min<size_t>(result.capacity(), std::numeric_limits<int>::max()), 1);
for (;;) {
UErrorCode status = U_ZERO_ERROR;
result.resize(len);
len = getTimeZoneIDForWindowsID(info.TimeZoneKeyName, -1, nullptr,
&result[0], len, &status);
len = static_cast<std::size_t>(
getTimeZoneIDForWindowsID(info.TimeZoneKeyName, -1, nullptr, &result[0],
static_cast<int>(len), &status));
if (U_SUCCESS(status)) {
return Utf16ToUtf8(result.data(), len);
}
Expand Down