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fix: Compile fix for MSVC 2022 in C++20 mode #778

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Merged
JEnoch merged 7 commits into from
Apr 19, 2026
+21 −17
Merged

fix: Compile fix for MSVC 2022 in C++20 mode #778

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cd47290
fix: Compile fix for MSVC 2022
jmachowinski Apr 15, 2026
6c2b0c5
second try
jmachowinski Apr 15, 2026
15f2dbd
fix: Fix compilation on c++17 / linux platforms
jmachowinski Apr 17, 2026
3ac9818
Use only c++17 features
jmachowinski Apr 17, 2026
f864675
fix: remove unnecessary move in bytes.hxx
jmachowinski Apr 17, 2026
3e3ab7e
chore: clang-format
Apr 18, 2026
d0602b8
make clang-format happy
JEnoch Apr 19, 2026
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34 changes: 19 additions & 15 deletions include/zenoh/api/bytes.hxx
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Original file line number Diff line number Diff line change
Expand Up @@ -64,11 +64,12 @@ class Bytes : public Owned<::z_owned_bytes_t> {
template <class Allocator>
Bytes(std::vector<uint8_t, Allocator>&& v) : Bytes() {
std::vector<uint8_t, Allocator>* ptr = new std::vector<uint8_t, Allocator>(std::move(v));
auto d = [p = ptr]() mutable { delete p; };
using D = decltype(d);
using Dval = std::remove_reference_t<D>;
using DroppableType = typename detail::closures::Droppable<Dval>;
auto drop = DroppableType::into_context(std::move(d));
struct VectorDeleter {
std::vector<uint8_t, Allocator>* ptr;
void operator()() { delete ptr; };
};
using DroppableType = typename detail::closures::Droppable<VectorDeleter>;
auto drop = DroppableType::into_context(std::move(VectorDeleter({.ptr = ptr})));
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@DenisBiryukov91 DenisBiryukov91 Apr 17, 2026

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this is not a valid C++17 code, aggregate initialization is only available, starting from C++20. Just into_context(std::move(VectorDeleter{ptr})) (or even just into_context(VectorDeleter{ptr})) should be good enough, the question stays though why std::move on lambda fails ?

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@jmachowinski jmachowinski Apr 17, 2026

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Damn, your are right this is also an c++20 feature...

I honestly don't know why the move fails on msvc. From my point of view it is valid, and gcc and clang are fine with it...
The compile error is also not really helpful on this one.. (see ros2/rmw_zenoh#968 (comment) for details).

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@DenisBiryukov91 DenisBiryukov91 Apr 17, 2026

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Hm, I'm wondering will something simple like auto&& d = [p = ptr]() mutable { delete p; }; solve the problem ?

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@jmachowinski jmachowinski Apr 17, 2026

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just tried it, nope...

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@jmachowinski jmachowinski Apr 17, 2026

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The ros2 CI has just enforced c++20 as minimum, so now the compiler error is also visible there in english :
https://ci.ros2.org/job/ci_windows/27622/console

Any more ideas on what to try ?

::z_bytes_from_buf(interop::as_owned_c_ptr(*this), ptr->data(), ptr->size(),
detail::closures::_zenoh_drop_with_context, drop);
}
Expand All @@ -89,11 +90,12 @@ class Bytes : public Owned<::z_owned_bytes_t> {
/// @brief Construct by moving a string.
Bytes(std::string&& v) : Bytes() {
std::string* ptr = new std::string(std::move(v));
auto d = [p = ptr]() mutable { delete p; };
using D = decltype(d);
using Dval = std::remove_reference_t<D>;
using DroppableType = typename detail::closures::Droppable<Dval>;
auto drop = DroppableType::into_context(std::move(d));
struct StringDeleter {
std::string* ptr;
void operator()() { delete ptr; }
};
using DroppableType = typename detail::closures::Droppable<StringDeleter>;
auto drop = DroppableType::into_context(std::move(StringDeleter({.ptr = ptr})));
::z_bytes_from_buf(interop::as_owned_c_ptr(*this), reinterpret_cast<uint8_t*>(ptr->data()), ptr->size(),
detail::closures::_zenoh_drop_with_context, drop);
}
Expand All @@ -108,11 +110,13 @@ class Bytes : public Owned<::z_owned_bytes_t> {
Bytes(uint8_t* ptr, size_t len, Deleter deleter) : Bytes() {
static_assert(std::is_invocable_r<void, Deleter, uint8_t*>::value,
"deleter should be callable with the following signature: void deleter(uint8_t* data)");
auto d = [p = ptr, del = std::move(deleter)]() mutable { del(p); };
using D = decltype(d);
using Dval = std::remove_reference_t<D>;
using DroppableType = typename detail::closures::Droppable<Dval>;
auto drop = DroppableType::into_context(std::move(d));
struct CustomDeleter {
uint8_t* ptr;
Deleter deleter;
void operator()() { deleter(ptr); }
};
using DroppableType = typename detail::closures::Droppable<CustomDeleter>;
auto drop = DroppableType::into_context(std::move(CustomDeleter({.ptr = ptr, .deleter = std::move(deleter)})));
::z_bytes_from_buf(interop::as_owned_c_ptr(*this), ptr, len, detail::closures::_zenoh_drop_with_context, drop);
}

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