charls/default.ruleset.md

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# Comments on disabled Visual Studio C++ Core Guidelines Rules

This document contains the rationales why some Microsoft
C++ warnings are disabled in the file default.ruleset
It is not possible to add this info to the .ruleset file itself as edit actions
with the VS GUI would cause the comments to get lost.
Most of disabled rules\warning are based on the C++ Core Guidelines that require
usage of the gsl helper library.

## Warnings

- C26426: Global initializer calls a non-constexpr function 'xxx'  
**Rationale**: many false warnings. CharLS is a library, globals are correctly initialized.

- C26429: Symbol 'xxx' is never tested for nullness, it can be marked as not_null (f.23).  
**Rationale**: Prefast attributes are better.

- C26446: Prefer to use gsl::at() instead of unchecked subscript operator.  
 **Rationale**: CharLS require good performance, gsl:at() cannot be used. debug STL already checks.

- C26459: You called an STL function '' with a raw pointer parameter. Consider wrapping your range in a gsl::span and pass as a span iterator (stl.1)  
**Rationale**: gsl:span() cannot be used. Update to std:span when available (C++20).

- C26472: Don't use static_cast for arithmetic conversions  
 **Rationale**: can only be solved with gsl::narrow_cast

- C26481: Do not pass an array as a single pointer.  
**Rationale**: gsl::span is not available.

- C26482: Only index into arrays using constant expressions.  
**Rationale**: static analysis can verify access, std::array during runtime (debug)

- C26490: Don't use reinterpret_cast  
**Rationale**: required to cast unsigned char\* to char\*.

- C26494: Variable 'x' is uninitialized. Always initialize an object  
**Rationale**: many false warnings, already covered with other analyzers.