gsl-lite v1.0.0

Breaking changes

namespace gsl_lite and <gsl-lite/gsl-lite.hpp>

gsl-lite now lives in the single header file <gsl-lite/gsl-lite.hpp>, and all its symbols reside in namespace gsl_lite. By default, gsl-lite no longer defines a namespace gsl or the unprefixed Expects() and Ensures() macros for precondition and postcondition checking.

This change enables coexistence with Microsoft GSL or other GSL implementations. (#194)

To minimize the impact of the breaking changes, gsl-lite introduces an optional GSL compatibility mode controlled by the new configuration switch gsl_FEATURE_GSL_COMPATIBILITY_MODE, which is is disabled by default and can be enabled by defining gsl_FEATURE_GSL_COMPATIBILITY_MODE=1. This should not be used in public header files of libraries which use gsl-lite because it precludes the use of Microsoft GSL in the same translation unit.

The legacy header file <gsl/gsl-lite.hpp> now forwards to <gsl-lite/gsl-lite.hpp> and implicitly enables the GSL compatibility mode. When the legacy header is included, it emits a warning message which urges to either migrate to header <gsl-lite/gsl-lite.hpp>, namespace gsl_lite, and the prefixed contract checking macros gsl_Expects() and gsl_Ensures(), or to explicitly request GSL compatibility by defining gsl_FEATURE_GSL_COMPATIBILITY_MODE=1.

Please refer to the migration guide in the gsl-lite documentation for guidance on how to adapt your code.

Other changes

• span<> now implements static extents. This was achieved by adapting the span<> implementation from Microsoft GSL, back-porting it to support C++98 and older compilers. (#153; 14c9f730efe2d056fb580c15402a93a21cdec01e)

• span<>::iterator now is a proper class instead of a pointer. Span iterator operations are now checked with gsl_ExpectsDebug(). (#153; 14c9f730efe2d056fb580c15402a93a21cdec01e)

• gsl-lite v1 has different defaults for the numerous configuration options and switches:

  • gsl_FEATURE_STRING_SPAN:
    Version-1 default: gsl_FEATURE_STRING_SPAN=0
    Version-0 default: gsl_FEATURE_STRING_SPAN=1
    Reason: string spans are no longer part of the GSL specification.
  • gsl_FEATURE_BYTE:
    Version-1 default: gsl_FEATURE_BYTE=0
    Version-0 default: gsl_FEATURE_BYTE=1
    Reason: byte has been superseded by std::byte in C++17.
  • : Version-1 default: Version-0 default:

Fixes

• In C++98 mode, the faulty definition of the internal function macro gsl_STATIC_ASSERT_() was corrected, fixing an unwanted predicate inversion for some internal compile-time checks. (ad2ffbdfec329c66194fa7f4676114f64e8d8cbf)
• Contract check macros now always expand to an expression or a statement, which avoids compiler warnings. (4654752fdcd8cf6684360c705c72d8f3d28694ef)

Deprecations and removals

• Deprecated unsafe span<> member function as_span<>(). (14c9f730efe2d056fb580c15402a93a21cdec01e)
• Removed Owner() and implicit macros, which already were disabled by default. (10952e7e58f542ff741ec329e01427101b309e55)
• Removed many deprecated functions: (6163d1366dde01ce0ceff62b0c74b686f8eb698b, 14c9f730efe2d056fb580c15402a93a21cdec01e)
  • as_writeable_bytes()
  • basic_string_span<> member function operator() for indexing
  • span<> constructor overloads and make_span() overloads accepting reference arguments, unique_ptr<>, or shared_ptr<> arguments
  • span<> member functions at() and operator() for indexing
  • span<> member functions length(), length_bytes(), as_bytes(), as_writeable_bytes()
• Removed the non-templated functions finally(), on_return(), and on_error() for C++98. (6bae7681f3bf33f539677b70076fbfba33ee4fd7)

Full Changelog: https://github.com/gsl-lite/gsl-lite/compare/v0.43.0...v1.0.0