diff --git a/docs/error-messages/compiler-warnings/compiler-warning-level-4-c4706.md b/docs/error-messages/compiler-warnings/compiler-warning-level-4-c4706.md index 6fa2feebb00..d31d01fd410 100644 --- a/docs/error-messages/compiler-warnings/compiler-warning-level-4-c4706.md +++ b/docs/error-messages/compiler-warnings/compiler-warning-level-4-c4706.md @@ -1,70 +1,65 @@ --- description: "Learn more about: Compiler Warning (level 4) C4706" title: "Compiler Warning (level 4) C4706" -ms.date: "11/04/2016" +ms.date: "3/5/2025" f1_keywords: ["C4706"] helpviewer_keywords: ["C4706"] -ms.assetid: 89cd3f4f-812c-4a4b-9426-65a5a6d1b99c --- # Compiler Warning (level 4) C4706 -assignment within conditional expression +> assignment used as a condition -The test value in a conditional expression was the result of an assignment. +The test value in a conditional expression is the result of an assignment. An assignment has a value (the value on the left side of the assignment) that can be used legally in another expression, including a test expression. The following sample generates C4706: ```cpp -// C4706a.cpp // compile with: /W4 int main() { int a = 0, b = 0; - if ( a = b ) // C4706 + if (a = b) // C4706 { } } ``` -The warning will occur even if you double the parentheses around the test condition: +Suppress the warning with `((`*expression*`))`. For example: ```cpp -// C4706b.cpp // compile with: /W4 int main() { int a = 0, b = 0; - if ( ( a = b ) ) // C4706 + if ((a = b)) // No warning { } } ``` -If your intention is to test a relation and not to make an assignment, use the `==` operator. For example, the following line tests whether a and b are equal: +If your intention is to test a relation, not to make an assignment, use the `==` operator. For example, the following tests whether a and b are equal: ```cpp -// C4706c.cpp // compile with: /W4 int main() { int a = 0, b = 0; - if ( a == b ) + if (a == b) { } } ``` -If you intend to make your test value the result of an assignment, test to ensure that the assignment is non-zero or not null. For example, the following code will not generate this warning: +If you intend to make your test value the result of an assignment, test to ensure that the assignment is non-zero or non-null. For example, the following code doesn't generate this warning: ```cpp -// C4706d.cpp // compile with: /W4 int main() { int a = 0, b = 0; - if ( ( a = b ) != 0 ) + if ((a = b) != 0) { } } diff --git a/docs/sanitizers/asan-known-issues.md b/docs/sanitizers/asan-known-issues.md index 192fd05d583..5a06490c03d 100644 --- a/docs/sanitizers/asan-known-issues.md +++ b/docs/sanitizers/asan-known-issues.md @@ -1,7 +1,7 @@ --- title: "AddressSanitizer known issues" description: "Technical description of the AddressSanitizer for Microsoft C/C++ known issues." -ms.date: 1/28/2025 +ms.date: 3/5/2025 helpviewer_keywords: ["AddressSanitizer known issues"] --- @@ -23,8 +23,6 @@ These options and functionality are incompatible with [`/fsanitize=address`](../ - [C++ AMP](../parallel/amp/cpp-amp-overview.md) is unsupported, and should be disabled. - [Universal Windows Platform](../cppcx/universal-windows-apps-cpp.md) (UWP) applications are unsupported. - [Special case list](https://clang.llvm.org/docs/SanitizerSpecialCaseList.html) files are unsupported. -- [MFC](../mfc/mfc-concepts.md) using the optional [`alloc_dealloc_mismatch`](error-alloc-dealloc-mismatch.md) runtime option is unsupported. -- [`_CrtDumpMemoryLeaks`](../c-runtime-library/reference/crtdumpmemoryleaks.md) is unsupported, and should be disabled. ## Standard library support @@ -56,6 +54,12 @@ int main() { } ``` +## Overriding operator new and delete + +AddressSanitizer (ASAN) has a custom version of `operator new` and `operator delete` that it uses to find more allocation errors like [`alloc_dealloc_mismatch`](error-alloc-dealloc-mismatch.md). Running the linker with [`/INFERASANLIBS`](../build/reference/inferasanlibs.md) ensures that ASAN's `new`/`delete` override has low precedence, so that the linker chooses any `operator new` or `operator delete` overrides in other libraries over ASAN's custom versions. When this happens, ASAN may not be able to catch some errors that rely on its custom `operator new` and `operator delete`. + +[MFC](../mfc/mfc-concepts.md) includes custom overrides for `operator new` and `operator delete` and so might miss errors like [`alloc_dealloc_mismatch`](error-alloc-dealloc-mismatch.md). + ## Windows versions As there are dependencies with specific Windows versions, support is focused on Windows 10. MSVC AddressSanitizer was tested on 10.0.14393 (RS1), and 10.0.21323 (prerelease insider build). [Report a bug](https://aka.ms/feedback/report?space=62) if you run into issues.