Native Windows support with Microsoft Windows Visual Studio (MSVC)#5890
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SamuelMarks wants to merge 7 commits into
Open
Native Windows support with Microsoft Windows Visual Studio (MSVC)#5890SamuelMarks wants to merge 7 commits into
SamuelMarks wants to merge 7 commits into
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This was referenced May 23, 2026
boquan-fang
reviewed
May 26, 2026
| * Runs _thecleanup function on _thealloc once _thealloc went out of scope | ||
| */ | ||
| #if defined(_MSC_VER) | ||
| #define DEFER_CLEANUP(_thealloc, _thecleanup) _thealloc |
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I don't think disable DEFER_CLEANUP on Windows is the right decision. This macros is used to ensure that s2n-tls won't leak memory and all dynamically allocated memory are properly cleaned up.
Disabling DEFER_CLEANUP via zeroes on MSVC removes critical failsafe memory management that handles early returns across the codebase. Instead of forcing upstream macros to compile as C++ RAII or stripping them entirely, we implement a python AST-rewriting pass.
fix_defer_cleanup.py intercepts DEFER_CLEANUP calls during build setup. It copies the source files, parses the variable initialization and cleanup function, and dynamically wraps the remainder of the scope in a native MSVC \__try { ... } __finally { cleanup_fn(&var); }\ block.
CMakeLists.txt is then patched to source these rewritten C files, ensuring perfect runtime safety without modifying any original code.
Includes fix for conditionally compiled DEFER_CLEANUP scopes and vcpkg.json baseline requirement.
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Goal
Add native Windows support
Why
Windows has many users
How
Shims, mostly.
Callouts
N/A
Testing
It builds! - Can port the test suite too if you want.
Related
Resolve #4018
By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.