GSL Lite: Guidelines Support Library for C++98, C++11 up

GSL Lite is based on the Microsoft Guidelines Support Library (GSL).

Contents

Example usage

#include "gsl/gsl-lite.hpp"

using namespace gsl;

int * use( not_null<int *> p ) 
{
    // use p knowing it's not nullptr, NULL or 0.
    
    return p;
}

struct Widget
{
    Widget() : owned_ptr( new int(42) ) {}
    ~Widget() { delete owned_ptr; }

    void work() { non_owned_ptr = use( owned_ptr ); }
    
    owner<int *> owned_ptr;	// if alias template support
//  Owner(int *) owned_ptr;	// C++98 up
    int * non_owned_ptr;
};

int main()
{
    Widget w;
    w.work();
}

Compile and run

prompt>g++ -std=c++03 -Wall -I../include -o 01-basic.exe 01-basic.cpp && 01-basic.exe

In a nutshell

gsl-lite is a single-file header-only variant of Microsoft's implementation of the Guidelines Support Library (GSL) adapted for C++98, C++03. It should also work when compiled as C++11, C++14, C++17.

The Guidelines Support Library (GSL) contains functions and types that are suggested for use by the C++ Core Guidelines maintained by the Standard C++ Foundation. The library includes types like owner<>, not_null<>, span<>, string_span and others.

gsl-lite recognizes when it is compiled for the CUDA platform and decorates functions (methods) with __host__ and __device__. See also section API macro.

License

gsl-lite uses the MIT license.

Dependencies

gsl-lite has no other dependencies than the C++ standard library.

Installation and use

gsl-lite is a single-file header-only library. There are various ways to use it in your project.

Contents

As copied header

Put a copy of gsl-lite.hpp located in folder include/gsl directly into the project source tree or somewhere reachable from your project, for example in project-root/include/gsl. If you like to refer to gsl-lite as gsl, also copy the file gsl. A minimal CMake setup using this header might look as follows.

In project root folder:

cmake_minimum_required( VERSION 3.5 FATAL_ERROR )

project( use-gsl-lite LANGUAGES CXX )

# Provide #include access to gsl-lite as 'gsl/gsl' and as 'gsl/gsl-lite.hpp': 

set( GSL_LITE_INCLUDE_DIR include )  # adapt as necessary
add_library( gsl INTERFACE )
target_include_directories( gsl INTERFACE ${GSL_LITE_INCLUDE_DIR} )

# Build program from src:

add_subdirectory( src )

In folder src:

cmake_minimum_required( VERSION 3.5 FATAL_ERROR )

project( program-using-gsl-lite LANGUAGES CXX )

# Make program executable:

set( SOURCES main.cpp)
add_executable( program ${SOURCES} )
target_link_libraries( program PRIVATE gsl )

As external Git project

Another approach is to automatically fetch the entire gsl-lite repository from github and configure it as an external project.

cmake_minimum_required( VERSION 3.5 FATAL_ERROR )

project( use-gsl-lite LANGUAGES CXX )

# Set default ExternalProject root directory and add gsl-lite:

set( GSL_LITE_URL https://github.com/martinmoene/gsl-lite.git )

include( ExternalProject )
find_package( Git REQUIRED )

set_directory_properties( PROPERTIES EP_PREFIX ${CMAKE_BINARY_DIR}/3rd_party )

ExternalProject_Add(
    gsl-extern
    GIT_REPOSITORY ${GSL_LITE_URL}
    TIMEOUT 10
    UPDATE_COMMAND ${GIT_EXECUTABLE} pull
    CONFIGURE_COMMAND ""
    BUILD_COMMAND ""
    INSTALL_COMMAND ""
    LOG_DOWNLOAD ON
   )

# Provide #include access to gsl-lite as 'gsl/gsl' and as 'gsl/gsl-lite.hpp': 

ExternalProject_Get_Property( gsl-extern SOURCE_DIR )
set( GSL_LITE_INCLUDE_DIR ${SOURCE_DIR}/include CACHE INTERNAL "Include folder for gsl-lite")

add_library( gsl INTERFACE )
target_include_directories( gsl INTERFACE ${GSL_LITE_INCLUDE_DIR} )

# Build program from src:

add_subdirectory( src )

In folder src:

cmake_minimum_required( VERSION 3.5 FATAL_ERROR )

project( program-using-gsl-lite LANGUAGES CXX )

# Make program executable:

set( SOURCES main.cpp)
add_executable( program ${SOURCES} )
target_link_libraries( program PRIVATE gsl )

This setup brings in more than you need, but also makes it easy to update gsl-lite to the latest version. See example/cmake-extern for a complete example.

As CMake package

First install the gsl-lite CMake package from its source, for example:
```
 cd ./gsl-lite
 cmake -H. -B../_build -G"Unix Makefiles" -DCMAKE_INSTALL_PREFIX="~/dev"
 cmake --build ../_build --target install
```
See also script/install-gsl-pkg.py that can perform these steps for you. It also lets you control compiler and build configuration.

Next, you can use the gsl-lite CMake package, for example:

cmake_minimum_required( VERSION 3.5 FATAL_ERROR )

find_package( gsl-lite "0.33" REQUIRED )

project( program-using-gsl-lite LANGUAGES CXX )

add_executable(        program main.cpp )
target_link_libraries( program PRIVATE gsl::gsl-lite )

Configure and build:

 cd ./gsl-lite/example/cmake-pkg
 cmake -H. -B../_build -G"Unix Makefiles" -DCMAKE_INSTALL_PREFIX=_stage -DCMAKE_PREFIX_PATH="~/dev"
 cmake --build ../_build

See example/cmake-pkg/Readme.md for a complete example.

As Conan package

For the conan package manager, follow these steps:

Add nonstd-lite to the conan remotes:

 conan remote add nonstd-lite https://api.bintray.com/conan/martinmoene/nonstd-lite

Add a reference to gsl-lite to the requires section of your project's conanfile.txt file:
```
 [requires]
 gsl-lite/0.34.0@nonstd-lite/stable
```
Run conan's install command:
```
 conan install
```

As Conda package

For the conda package manager, first use one of these options to install gsl-lite from the conda-forge channel:

Install it in the current environment:
```
 conda install -c conda-forge gsl-lite
```
Install it in a different environment (named env_name in this example):
```
 conda install -n env_name -c conda-forge gsl-lite
```
Create a new environment containing gsl-lite (and possibly other packages, appended at the end of the command):
```
 conda create -n env_name -c conda-forge gsl-lite cmake
```
Add it to an already existing environment.yml file, and update the environment using:
```
 conda env update
```

Then activate the environment using conda activate env_name (if not already activated) and proceed using the instructions from step 2 of "As CMake package". Note that it's also useful to have the cmake package in the same environment, and explicitly passing -DCMAKE_INSTALL_PREFIX is not necessary.

Synopsis

Contents

API macro

-Dgsl_api=""
Functions (methods) are decorated with gsl_api. At default gsl_api is defined empty for non-CUDA platforms and __host__ __device__ for the CUDA platform. Define this macro to specify your own function decoration.

Standard selection macro

-Dgsl_CPLUSPLUS=199711L
Define this macro to override the auto-detection of the supported C++ standard, if your compiler does not set the __cplusplus macro correctly.

Feature selection macros

-Dgsl_FEATURE_WITH_CONTAINER_TO_STD=99
Define this to the highest C++ standard (98, 3, 11, 14, 17, 20) you want to include tagged-construction via with_container. Default is 99 for inclusion with any standard.

-Dgsl_FEATURE_MAKE_SPAN_TO_STD=99
Define this to the highest C++ standard (98, 3, 11, 14, 17, 20) you want to include make_span() creator functions. Default is 99 for inclusion with any standard.

-Dgsl_FEATURE_BYTE_SPAN_TO_STD=99
Define this to the highest C++ standard (98, 3, 11, 14, 17, 20) you want to include byte_span() creator functions. Default is 99 for inclusion with any standard.

-Dgsl_FEATURE_IMPLICIT_MACRO=0
Define this macro to 1 to provide the implicit macro. Default is 0.

-Dgsl_FEATURE_OWNER_MACRO=1
At default macro Owner() is defined for all C++ versions. This may be useful to transition from a compiler that doesn't provide alias templates to one that does. Define this macro to 0 to omit the Owner() macro. Default is 1.

-Dgsl_FEATURE_EXPERIMENTAL_RETURN_GUARD=0
Provide experimental types final_action_return and final_action_error and convenience functions on_return() and on_error(). Default is 0.

Contract violation response macros

gsl-lite provides contract violation response control as suggested in proposal N4415.

-Dgsl_CONFIG_CONTRACT_LEVEL_ON
Define this macro to include both Expects and Ensures in the code. This is the default case.

-Dgsl_CONFIG_CONTRACT_LEVEL_OFF
Define this macro to exclude both Expects and Ensures from the code.

-Dgsl_CONFIG_CONTRACT_LEVEL_EXPECTS_ONLY
Define this macro to include Expects in the code and exclude Ensures from the code.

-Dgsl_CONFIG_CONTRACT_LEVEL_ENSURES_ONLY
Define this macro to exclude Expects from the code and include Ensures in the code.

-Dgsl_CONFIG_CONTRACT_VIOLATION_TERMINATES
Define this macro to call std::terminate() on a GSL contract violation in Expects, Ensures and narrow. This is the default case.

-Dgsl_CONFIG_CONTRACT_VIOLATION_THROWS
Define this macro to throw a std::runtime_exception-derived exception gsl::fail_fast instead of calling std::terminate() on a GSL contract violation in Expects, Ensures and throw a std::exception-derived exception narrowing_error on discarding information in narrow.

-Dgsl_CONFIG_CONTRACT_VIOLATION_CALLS_HANDLER
Define this macro to call a user-defined handler function gsl::fail_fast_assert_handler() instead of calling std::terminate() on a GSL contract violation in Expects and Ensures, and call std::terminate() on discarding information in narrow. The user is expected to supply a definition matching the following signature:

namespace gsl {
	gsl_api gsl_constexpr14 void fail_fast_assert_handler(
		char const * const expression, char const * const message,
		char const * const file, int line );
}

Microsoft GSL compatibility macros

-DGSL_UNENFORCED_ON_CONTRACT_VIOLATION
Equivalent to -Dgsl_CONFIG_CONTRACT_LEVEL_OFF.

-DGSL_THROW_ON_CONTRACT_VIOLATION
Equivalent to -Dgsl_CONFIG_CONTRACT_VIOLATION_THROWS.

-DGSL_TERMINATE_ON_CONTRACT_VIOLATION
Equivalent to -Dgsl_CONFIG_CONTRACT_VIOLATION_TERMINATES.

Other configuration macros

-Dgsl_CONFIG_DEPRECATE_TO_LEVEL=0
Define this to and including the level you want deprecation; see table Deprecation below. Default is 0 for no deprecation.

-Dgsl_CONFIG_SPAN_INDEX_TYPE=size_t
Define this macro to the type to use for indices in span and basic_string_span. Microsoft's GSL uses std::ptrdiff_t. Default for gsl lite is size_t.

-Dgsl_CONFIG_NOT_NULL_EXPLICIT_CTOR=0
Define this macro to 1 to make not_null's constructor explicit. Default is 0. Note that in Microsoft's GSL the constructor is explicit. For implicit construction you can also use the gsl lite-specific not_null-derived class not_null_ic.

-Dgsl_CONFIG_NOT_NULL_GET_BY_CONST_REF=0
Define this macro to 1 to have not_null<>::get() and relatives return by T const & instead of T. This may improve performance with types that have an expensive copy-constructor. Default is 0 for T.

-Dgsl_CONFIG_ALLOWS_NONSTRICT_SPAN_COMPARISON=1
Define this macro to 0 to omit the ability to compare spans of different types, e.g. of different const-volatile-ness. To be able to compare a string_span with a cstring_span, non-strict span comparison must be available. Default is 1.

-Dgsl_CONFIG_ALLOWS_UNCONSTRAINED_SPAN_CONTAINER_CTOR=0
Define this macro to 1 to add the unconstrained span constructor for containers for pre-C++11 compilers that cannot constrain the constructor. This constructor may prove too greedy and interfere with other constructors. Default is 0.

Note: an alternative is to use the constructor tagged with_container: span<value_type> s(with_container, cont).

-Dgsl_CONFIG_CONFIRMS_COMPILATION_ERRORS=0
Define this macro to 1 to experience the by-design compile-time errors of the GSL components in the test suite. Default is 0.

Features

See also section GSL: Guidelines Support Library of the C++ Core Guidelines [9].

Feature / library	GSL	M-GSL	GSL-Lite	Notes
1.Lifetime safety
1.1 Indirection
not_null<>	✓	✓	✓	Wrap any indirection and enforce non-null, see also Other configuration macros
not_null_ic<>	-	-	✓	not_null with implicit constructor, allowing copy-initialization
1.2 Ownership
owner<>	✓	✓	>=C++11	Owned raw pointers
Owner()	-	-	✓	Macro for pre-C++11; see also Feature selection macros
unique_ptr<>	✓	✓	>=C++11	std::unique_ptr<>
unique_ptr<>	-	-	< C++11	VC10, VC11
shared_ptr<>	✓	✓	>=C++11	std::shared_ptr<>
shared_ptr<>	-	-	< C++11	VC10, VC11 see also Extract Boost smart pointers
stack_array<>	✓	-	-	A stack-allocated array, fixed size
dyn_array<>	?	-	-	A heap-allocated array, fixed size
2.Bounds safety
2.1 Tag Types
zstring	✓	✓	✓	a char* (C-style string)
wzstring	-	✓	✓	a wchar_t* (C-style string)
czstring	✓	✓	✓	a const char* (C-style string)
cwzstring	-	✓	✓	a const wchar_t* (C-style string)
2.2 Views
span<>	✓	✓	1D views	A view of contiguous T's, replace (*,len), see also proposal p0122
span_p<>	✓	-	-	A view of contiguous T's that ends at the first element for which predicate(*p) is true
make_span()	-	✓	✓	Create a span
byte_span()	-	-	✓	Create a span of bytes from a single object
as_bytes()	-	✓	✓	A span as bytes
as_writeable_bytes	-	✓	✓	A span as writeable bytes
basic_string_span<>	-	✓	✓	See also proposal p0123
string_span	✓	✓	✓	basic_string_span<char>
wstring_span	-	✓	✓	basic_string_span<wchar_t >
cstring_span	✓	✓	✓	basic_string_span<const char>
cwstring_span	-	✓	✓	basic_string_span<const wchar_t >
zstring_span	-	✓	✓	basic_zstring_span<char>
wzstring_span	-	✓	✓	basic_zstring_span<wchar_t >
czstring_span	-	✓	✓	basic_zstring_span<const char>
cwzstring_span	-	✓	✓	basic_zstring_span<const wchar_t >
ensure_z()	-	✓	✓	Create a cstring_span or cwstring_span
to_string()	-	✓	✓	Convert a string_span to std::string or std::wstring
2.3 Indexing
at()	✓	✓	>=C++11	Bounds-checked way of accessing static arrays, std::array, std::vector
at()	-	-	< C++11	static arrays, std::vector std::array : VC11
3. Assertions
Expects()	✓	✓	✓	Precondition assertion
Ensures()	✓	✓	✓	Postcondition assertion
4. Utilities
index	✓	✓	✓	type for container indexes, subscripts, sizes, see Other configuration macros
byte	-	✓	✓	byte type, see also proposal p0298
final_action<>	✓	✓	>=C++11	Action at the end of a scope
final_action	-	-	< C++11	Currently only void(*)()
finally()	✓	✓	>=C++11	Make a final_action<>
finally()	-	-	< C++11	Make a final_action
final_action_return	-	-	< C++11	Currently only void(*)(), experimental
on_return()	-	-	>=C++11	Make a final_action_return<>, experimental
on_return()	-	-	< C++11	Make a final_action_return, experimental
final_action_error	-	-	< C++11	Currently only void(*)(), experimental
on_error()	-	-	>=C++11	Make a final_action_error<>, experimental
on_error()	-	-	< C++11	Make a final_action_error, experimental
narrow_cast<>	✓	✓	✓	Searchable narrowing casts of values
narrow()	✓	✓	✓	Checked version of narrow_cast()
[[implicit]]	✓	-	C++??	Symmetric with explicit
implicit	-	-	✓	Macro, see Feature selection macros
move_owner	?	-	-	...
5. Algorithms
copy()				Copy from source span to destination span
size()				Size of span, unsigned
ssize()				Size of span, signed
6. Concepts
...

Note: GSL Lite treats VC12 (VS2013) and VC14 (VS2015) as C++11 (gsl_CPP11_OR_GREATER: 1).

Deprecation

The following features are deprecated since the indicated version. See macro gsl_CONFIG_DEPRECATE_TO_LEVEL on how to control deprecation using the indicated level.

Version	Level	Feature / Notes
0.31.0	5	span( std::nullptr_t, index_type )
		span( pointer, index_type ) is used
0.31.0	5	span( U *, index_type size )
		span( pointer, index_type ) is used
0.31.0	5	span( U (&arr)[N] )
		span( element_type (&arr)[N] ) is used
0.31.0	5	span( std::array< U, N > [const] & arr )
		span( std::array< value_type, N > [const] & arr ) is used
0.29.0	4	span::span( std::shared_ptr const & p )
		Use span( p.get(), p.get() ? 1 : 0 ) or equivalent
0.29.0	4	span::span( std::unique_ptr const & p )
		Use Use span( p.get(), p.get() ? 1 : 0 ) or equivalent
0.29.0	3	span::length()
		Use span::size()
0.29.0	3	span::length_bytes()
		Use span::size_bytes()
0.17.0	2	member span::as_bytes(), span::as_writeable_bytes()
		—
0.7.0	1	gsl_CONFIG_ALLOWS_SPAN_CONTAINER_CTOR
		Use gsl_CONFIG_ALLOWS_UNCONSTRAINED_SPAN_CONTAINER_CTOR, or consider span(with_container, cont).

Reported to work with

The table below mentions the compiler versions gsl-lite is reported to work with.

OS	Compiler	Where	Versions
GNU/Linux	Clang/LLVM	Travis	3.4, 3.4, 3.6, 3.7, 3.8, 3.9, 4.0, 5.0
	GCC	Travis	5.4.1, 6.3.0, 7.2.0
OS X	?		?
Windows	Clang/LLVM		?
	GCC	Local	4.8.4, 4.9.2, 5.2.0, 7.2.0
	Visual C++ (Visual Studio)	Local Local AppVeyor	6 (6) via header gsl-lite-vc6.hpp (not up to date) 8 (2005), 10 (2010), 11 (2012), 12 (2013), 14 (2015), 15 (2017)
DOSBox	DJGPP	Local	DJGPP for GCC 7.2.0
FreeDOS	DJGPP	Local	DJGPP for GCC 7.2.0

Building the tests

To build the tests you need:

CMake, version 3.0 or later to be installed and in your PATH.
A suitable compiler.

The lest test framework is included in the test folder.

The following steps assume that the GSL Lite source code has been cloned into a directory named c:\gsl-lite.

Create a directory for the build outputs for a particular architecture.
Here we use c:\gsl-lite\build-win-x86-vc10.
```
 cd c:\gsl-lite
 md build-win-x86-vc10
 cd build-win-x86-vc10
```
Configure CMake to use the compiler of your choice (run cmake --help for a list).
```
 cmake -G "Visual Studio 10 2010" ..
```
Build the test suite in the Debug configuration (alternatively use Release).
```
 cmake --build . --config Debug
```
Run the test suite.
```
 ctest -V -C Debug
```

All tests should pass, indicating your platform is supported and you are ready to use gsl-lite. See the table with supported types and functions.

Other GSL implementations

Microsoft. Guidelines Support Library (GSL).
Vicente J. Botet Escriba. Guidelines Support Library (GSL).
Mattia Basaglia. CxxMiscLib gsl.hpp, tests.

Notes and references

C++ features in various Visual C++ compilers

[18] Visual CPP Team. C++0x Core Language Features In VC10: The Table. Microsoft. 6 April 2010.
[19] Visual CPP Team. C++11 Features in Visual C++ 11. Microsoft. 12 September 2011.
[20] Joel Coehoorn. C++11 features in Visual Studio 2012. StackOverflow. 14 September 2011.
[21] Stephan T. Lavavej. C++11/14 Features In Visual Studio 14 CTP3. Microsoft. 21 August 2014.
[22] Stephan T. Lavavej. C++11/14/17 Features In VS 2015 RTM. Microsoft. 19 June 2015.

Appendix

Contents

A.1 Extract Boost smart pointers

To obtain a subset of Boost only containing the smart pointers, use the bcp command like:

C:\Libraries\boost\boost_1_51>bin\bcp scoped_ptr.hpp shared_ptr.hpp weak_ptr.hpp make_shared.hpp C:\Libraries\boost-shared_ptr

The smart pointers of Boost 1.51 can be used with VC6.

A.2 Compile-time information

The version of gsl lite is available via tag [.version]. The following tags are available for information on the compiler and on the C++ standard library used: [.compiler], [.stdc++], [.stdlanguage] and [.stdlibrary].

A.3 GSL Lite test specification

Expects(): Allows a true expression
Ensures(): Allows a true expression
Expects(): Terminates on a false expression
Ensures(): Terminates on a false expression
at(): Terminates access to non-existing C-array elements
at(): Terminates access to non-existing std::array elements (C++11)
at(): Terminates access to non-existing std::vector elements
at(): Terminates access to non-existing std::initializer_list elements (C++11)
at(): Terminates access to non-existing gsl::span elements
at(): Allows to access existing C-array elements
at(): Allows to access existing std::array elements (C++11)
at(): Allows to access existing std::vector elements
at(): Allows to access std::initializer_list elements (C++11)
at(): Allows to access gsl::span elements
byte: Allows to construct from integral via static cast (C++17)
byte: Allows to construct from integral via byte() (C++17)
byte: Allows to construct from integral via to_byte()
byte: Allows to convert to integral via to_integer()
byte: Allows comparison operations
byte: Allows bitwise or operation
byte: Allows bitwise and operation
byte: Allows bitwise x-or operation
byte: Allows bitwise or assignment
byte: Allows bitwise and assignment
byte: Allows bitwise x-or assignment
byte: Allows shift-left operation
byte: Allows shift-right operation
byte: Allows shift-left assignment
byte: Allows shift-right assignment
byte: Provides constexpr non-assignment operations (C++11)
byte: Provides constexpr assignment operations (C++14)
byte: Provides hash support (C++11)
not_null<>: Disallows default construction (define gsl_CONFIG_CONFIRMS_COMPILATION_ERRORS)
not_null<>: Disallows construction from nullptr_t, NULL or 0 (define gsl_CONFIG_CONFIRMS_COMPILATION_ERRORS)
not_null<>: Disallows construction from a unique pointer to underlying type (define gsl_CONFIG_CONFIRMS_COMPILATION_ERRORS)
not_null<>: Disallows assignment from unrelated pointers (define gsl_CONFIG_CONFIRMS_COMPILATION_ERRORS)
not_null<>: Terminates construction from a null pointer value
not_null<>: Terminates construction from related pointer types for null pointer value
not_null<>: Terminates assignment from a null pointer value
not_null<>: Terminates assignment from related pointer types for null pointer value
not_null<>: Allows to construct from a non-null underlying pointer
not_null<>: Allows to construct from a non-null user-defined ref-counted type
not_null<>: Allows to construct from a non-null related pointer
not_null<>: Allows to construct from a not_null related pointer type
not_null<>: Allows assignment from a not_null related pointer type
not_null<>: Allows assignment from a non-null bare recast pointer
not_null<>: Allows implicit conversion to underlying type
not_null<>: Allows indirect member access
not_null<>: Allows dereferencing
not_null<>: Allows to compare equal to another not_null of the same type
not_null<>: Allows to compare unequal to another not_null of the same type
not_null<>: Allows to compare less than another not_null of the same type
not_null<>: Allows to compare less than or equal to another not_null of the same type
not_null<>: Allows to compare greater than another not_null of the same type
not_null<>: Allows to compare greater than or equal to another not_null of the same type
not_null<>: Allows to compare equal to a raw pointer of the same type
not_null<>: Allows to compare unequal to a raw pointer of the same type
not_null<>: Allows to compare less than a raw pointer of the same type
not_null<>: Allows to compare less than or equal to a raw pointer of the same type
not_null<>: Allows to compare greater than a raw pointer of the same type
not_null<>: Allows to compare greater than or equal to a raw pointer of the same type
owner<>: Disallows construction from a non-pointer type (define gsl_CONFIG_CONFIRMS_COMPILATION_ERRORS)
owner<>: Allows its use as the (pointer) type it stands for
Owner(): Allows its use as the (pointer) type it stands for
span<>: Disallows construction from a temporary value (C++11) (define gsl_CONFIG_CONFIRMS_COMPILATION_ERRORS)
span<>: Disallows construction from a C-array of incompatible type (define gsl_CONFIG_CONFIRMS_COMPILATION_ERRORS)
span<>: Disallows construction from a std::array of incompatible type (C++11) (define gsl_CONFIG_CONFIRMS_COMPILATION_ERRORS)
span<>: Terminates construction from a nullptr and a non-zero size (C++11)
span<>: Terminates construction from two pointers in the wrong order
span<>: Terminates construction from a null pointer and a non-zero size
span<>: Terminates creation of a sub span of the first n elements for n exceeding the span
span<>: Terminates creation of a sub span of the last n elements for n exceeding the span
span<>: Terminates creation of a sub span outside the span
span<>: Terminates access outside the span
span<>: Allows to default-construct
span<>: Allows to construct from a nullptr and a zero size (C++11)
span<>: Allows to construct from a single object (C++11)
span<>: Allows to construct from a const single object (C++11)
span<>: Allows to construct from two pointers
span<>: Allows to construct from two pointers to const
span<>: Allows to construct from a non-null pointer and a size
span<>: Allows to construct from a non-null pointer to const and a size
span<>: Allows to construct from a temporary pointer and a size
span<>: Allows to construct from a temporary pointer to const and a size
span<>: Allows to construct from any pointer and a zero size
span<>: Allows to construct from a C-array
span<>: Allows to construct from a const C-array
span<>: Allows to construct from a C-array with size via decay to pointer (potentially dangerous)
span<>: Allows to construct from a const C-array with size via decay to pointer (potentially dangerous)
span<>: Allows to construct from a std::initializer_list<> (C++11)
span<>: Allows to construct from a std::array<> (C++11)
span<>: Allows to construct from a std::array<> with const data (C++11) [deprecated-5]
span<>: Allows to construct from a container (std::vector<>)
span<>: Allows to construct from a temporary container (potentially dangerous)
span<>: Allows to tag-construct from a container (std::vector<>)
span<>: Allows to tag-construct from a temporary container (potentially dangerous)
span<>: Allows to construct from an empty gsl::shared_ptr (C++11) [deprecated-4]
span<>: Allows to construct from an empty gsl::unique_ptr (C++11) [deprecated-4]
span<>: Allows to construct from an empty gsl::unique_ptr (array, C++11) [deprecated-4]
span<>: Allows to construct from a non-empty gsl::shared_ptr (C++11) [deprecated-4]
span<>: Allows to construct from a non-empty gsl::unique_ptr (C++11) [deprecated-4]
span<>: Allows to construct from a non-empty gsl::unique_ptr (array, C++11) [deprecated-4]
span<>: Allows to copy-construct from another span of the same type
span<>: Allows to copy-construct from another span of a compatible type
span<>: Allows to move-construct from another span of the same type (C++11)
span<>: Allows to copy-assign from another span of the same type
span<>: Allows to move-assign from another span of the same type (C++11)
span<>: Allows to create a sub span of the first n elements
span<>: Allows to create a sub span of the last n elements
span<>: Allows to create a sub span starting at a given offset
span<>: Allows to create a sub span starting at a given offset with a given length
span<>: Allows to create an empty sub span at full offset
span<>: Allows to create an empty sub span at full offset with zero length
span<>: Allows forward iteration
span<>: Allows const forward iteration
span<>: Allows reverse iteration
span<>: Allows const reverse iteration
span<>: Allows to observe an element via array indexing
span<>: Allows to observe an element via call indexing
span<>: Allows to observe an element via at()
span<>: Allows to observe an element via data()
span<>: Allows to change an element via array indexing
span<>: Allows to change an element via call indexing
span<>: Allows to change an element via at()
span<>: Allows to change an element via data()
span<>: Allows to compare equal to another span of the same type
span<>: Allows to compare unequal to another span of the same type
span<>: Allows to compare less than another span of the same type
span<>: Allows to compare less than or equal to another span of the same type
span<>: Allows to compare greater than another span of the same type
span<>: Allows to compare greater than or equal to another span of the same type
span<>: Allows to compare to another span of the same type and different cv-ness (non-standard)
span<>: Allows to compare empty spans as equal
span<>: Allows to test for empty span via empty(), empty case
span<>: Allows to test for empty span via empty(), non-empty case
span<>: Allows to obtain the number of elements via size(), as configured
span<>: Allows to obtain the number of elements via ssize(), signed
span<>: Allows to obtain the number of elements via length() [deprecated-3]
span<>: Allows to obtain the number of bytes via size_bytes()
span<>: Allows to obtain the number of bytes via length_bytes() [deprecated-3]
span<>: Allows to swap with another span of the same type
span<>: Allows to view the elements as read-only bytes [deprecated-2 as member]
span<>: Allows to view and change the elements as writable bytes [deprecated-2 as member]
span<>: Allows to view the elements as a span of another type
span<>: Allows to change the elements from a span of another type
copy(): Allows to copy a span to another span of the same element type
copy(): Allows to copy a span to another span of a different element type
size(): Allows to obtain the number of elements in span via size(span), unsigned
ssize(): Allows to obtain the number of elements in span via ssize(span), signed
make_span(): (gsl_FEATURE_MAKE_SPAN=1)
make_span(): Allows to build from two pointers
make_span(): Allows to build from two const pointers
make_span(): Allows to build from a non-null pointer and a size
make_span(): Allows to build from a non-null const pointer and a size
make_span(): Allows to build from a C-array
make_span(): Allows to build from a const C-array
make_span(): Allows building from a std::initializer_list<> (C++11)
make_span(): Allows to build from a std::array<> (C++11)
make_span(): Allows to build from a const std::array<> (C++11)
make_span(): Allows to build from a container (std::vector<>)
make_span(): Allows to build from a const container (std::vector<>)
make_span(): Allows to build from a temporary container (potentially dangerous)
make_span(): Allows to tag-build from a container (std::vector<>)
make_span(): Allows to tag-build from a temporary container (potentially dangerous)
make_span(): Allows to build from an empty gsl::shared_ptr (C++11) [deprecated-4]
make_span(): Allows to build from an empty gsl::unique_ptr (C++11) [deprecated-4]
make_span(): Allows to build from an empty gsl::unique_ptr (array, C++11) [deprecated-4]
make_span(): Allows to build from a non-empty gsl::shared_ptr (C++11) [deprecated-4]
make_span(): Allows to build from a non-empty gsl::unique_ptr (C++11) [deprecated-4]
make_span(): Allows to build from a non-empty gsl::unique_ptr (array, C++11) [deprecated-4]
byte_span() (gsl_FEATURE_BYTE_SPAN=1)
byte_span(): Allows to build a span of gsl::byte from a single object
byte_span(): Allows to build a span of const gsl::byte from a single const object
string_span: Disallows construction of a string_span from a cstring_span (define gsl_CONFIG_CONFIRMS_COMPILATION_ERRORS)
string_span: Disallows construction of a string_span from a const std::string (define gsl_CONFIG_CONFIRMS_COMPILATION_ERRORS)
string_span: Allows to default-construct
string_span: Allows to construct from a nullptr (C++11)
string_span: Allows to construct a cstring_span from a const C-string
string_span: Allows to construct a string_span from a non-const C-string and size
string_span: Allows to construct a string_span from a non-const C-string begin and end pointer
string_span: Allows to construct a string_span from a non-const C-array
string_span: Allows to construct a string_span from a non-const std::string
string_span: Allows to construct a string_span from a non-const std::array (C++11)
string_span: Allows to construct a string_span from a non-const container (std::vector)
string_span: Allows to construct a string_span from a non-const container, via a tag (std::vector)
string_span: Allows to construct a cstring_span from a non-const C-string and size
string_span: Allows to construct a cstring_span from a non-const C-string begin and end pointer
string_span: Allows to construct a cstring_span from a non-const C-array
string_span: Allows to construct a cstring_span from a non-const std::string
string_span: Allows to construct a cstring_span from a non-const std::array (C++11)
string_span: Allows to construct a cstring_span from a non-const container (std::vector)
string_span: Allows to construct a cstring_span from a non-const container, via a tag (std::vector)
string_span: Allows to construct a cstring_span from a const C-string and size
string_span: Allows to construct a cstring_span from a non-const C-string begin and end pointer
string_span: Allows to construct a cstring_span from a const C-array
string_span: Allows to construct a cstring_span from a const std::string
string_span: Allows to construct a cstring_span from a const std::array (C++11)
string_span: Allows to construct a cstring_span from a const container (std::vector)
string_span: Allows to construct a cstring_span from a const container, via a tag (std::vector)
string_span: Allows to construct a wstring_span from a non-const C-string and size
string_span: Allows to construct a wstring_span from a non-const C-string begin and end pointer
string_span: Allows to construct a wstring_span from a non-const C-array
string_span: Allows to construct a wstring_span from a non-const std::wstring
string_span: Allows to construct a wstring_span from a non-const std::array (C++11)
string_span: Allows to construct a wstring_span from a non-const container (std::vector)
string_span: Allows to construct a wstring_span from a non-const container, via a tag (std::vector)
string_span: Allows to construct a cwstring_span from a non-const C-string and size
string_span: Allows to construct a cwstring_span from a non-const C-string begin and end pointer
string_span: Allows to construct a cwstring_span from a non-const C-array
string_span: Allows to construct a cwstring_span from a non-const std::wstring
string_span: Allows to construct a cwstring_span from a non-const std::array (C++11)
string_span: Allows to construct a cwstring_span from a non-const container (std::vector)
string_span: Allows to construct a cwstring_span from a non-const container, via a tag (std::vector)
string_span: Allows to construct a cwstring_span from a const C-string and size
string_span: Allows to construct a cwstring_span from a const C-string begin and end pointer
string_span: Allows to construct a cwstring_span from a const C-array
string_span: Allows to construct a cwstring_span from a const std::wstring
string_span: Allows to construct a cwstring_span from a const std::array (C++11)
string_span: Allows to construct a cwstring_span from a const container (std::vector)
string_span: Allows to construct a cwstring_span from a const container, via a tag (std::vector)
string_span: Allows to copy-construct from another span of the same type
string_span: Allows to copy-construct from another span of a compatible type
string_span: Allows to move-construct from another span of the same type (C++11)
string_span: Allows to copy-assign from another span of the same type
string_span: Allows to move-assign from another span of the same type (C++11)
string_span: Allows to create a sub span of the first n elements
string_span: Allows to create a sub span of the last n elements
string_span: Allows to create a sub span starting at a given offset
string_span: Allows to create a sub span starting at a given offset with a given length
string_span: Allows to create an empty sub span at full offset
string_span: Allows to create an empty sub span at full offset with zero length
string_span: Allows forward iteration
string_span: Allows const forward iteration
string_span: Allows reverse iteration
string_span: Allows const reverse iteration
string_span: Allows to observe an element via array indexing
string_span: Allows to observe an element via call indexing
string_span: Allows to observe an element via data()
string_span: Allows to change an element via array indexing
string_span: Allows to change an element via call indexing
string_span: Allows to change an element via data()
string_span: Allows to compare a string_span with another string_span
string_span: Allows to compare empty span to non-empty span
string_span: Allows to compare a string_span with a cstring_span
string_span: Allows to compare with types convertible to string_span
string_span: Allows to test for empty span via empty(), empty case
string_span: Allows to test for empty span via empty(), non-empty case
string_span: Allows to obtain the number of elements via length()
string_span: Allows to obtain the number of elements via size()
string_span: Allows to obtain the number of bytes via length_bytes()
string_span: Allows to obtain the number of bytes via size_bytes()
string_span: Allows to view the elements as read-only bytes
zstring_span: Allows to construct a zstring_span from a zero-terminated empty string (via span)
zstring_span: Allows to construct a zstring_span from a zero-terminated non-empty string (via span)
zstring_span: Terminates construction of a zstring_span from a non-zero-terminated string (via span)
zstring_span: Allows to construct a wzstring_span from a zero-terminated empty string (via span)
zstring_span: Allows to construct a wzstring_span from a zero-terminated non-empty string (via span)
zstring_span: Terminates construction of a wzstring_span from a non-zero-terminated string (via span)
zstring_span: Allows to use a zstring_span with a legacy API via member assume_z()
zstring_span: Allows to use a wzstring_span with a legacy API via member assume_z()
to_string(): Allows to explicitly convert from string_span to std::string
to_string(): Allows to explicitly convert from cstring_span to std::string
to_string(): Allows to explicitly convert from wstring_span to std::wstring
to_string(): Allows to explicitly convert from cwstring_span to std::wstring
ensure_z(): Disallows to build a string_span from a const C-string
ensure_z(): Disallows to build a wstring_span from a const wide C-string
ensure_z(): Allows to build a string_span from a non-const C-string
ensure_z(): Allows to build a cstring_span from a non-const C-string
ensure_z(): Allows to build a cstring_span from a const C-string
ensure_z(): Allows to build a wstring_span from a non-const wide C-string
ensure_z(): Allows to build a cwstring_span from a non-const wide C-string
ensure_z(): Allows to build a cwstring_span from a const wide C-string
ensure_z(): Allows to specify ultimate location of the sentinel and ensure its presence
operator<<: Allows printing a string_span to an output stream
operator<<: Allows printing a cstring_span to an output stream
operator<<: Allows printing a wstring_span to an output stream
operator<<: Allows printing a cwstring_span to an output stream
finally: Allows to run lambda on leaving scope
finally: Allows to run function (bind) on leaving scope
finally: Allows to run function (pointer) on leaving scope
finally: Allows to move final_action
on_return: Allows to perform action on leaving scope without exception (gsl_FEATURE_EXPERIMENTAL_RETURN_GUARD)
on_error: Allows to perform action on leaving scope via an exception (gsl_FEATURE_EXPERIMENTAL_RETURN_GUARD)
narrow_cast<>: Allows narrowing without value loss
narrow_cast<>: Allows narrowing with value loss
narrow<>(): Allows narrowing without value loss
narrow<>(): Terminates when narrowing with value loss
narrow<>(): Terminates when narrowing with sign loss

Name		Name	Last commit message	Last commit date
Latest commit History 727 Commits
cmake		cmake
example		example
include		include
project		project
script		script
test		test
.gitattributes		.gitattributes
.gitignore		.gitignore
.travis.yml		.travis.yml
CHANGES.txt		CHANGES.txt
CMakeLists.txt		CMakeLists.txt
LICENSE		LICENSE
README.md		README.md
appveyor.yml		appveyor.yml
conanfile.py		conanfile.py
gsl-lite.natvis		gsl-lite.natvis

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Mersive-Technologies/gsl-lite

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GSL Lite: Guidelines Support Library for C++98, C++11 up

Example usage

Compile and run

In a nutshell

License

Dependencies

Installation and use

As copied header

As external Git project

As CMake package

As Conan package

As Conda package

Synopsis

API macro

Standard selection macro

Feature selection macros

Contract violation response macros

Microsoft GSL compatibility macros

Other configuration macros

Features

Deprecation

Reported to work with

Building the tests

Other GSL implementations

Notes and references

Proposals, specification

Articles

Compiler feature testing

C++ features in various Visual C++ compilers

Appendix

A.1 Extract Boost smart pointers

A.2 Compile-time information

A.3 GSL Lite test specification

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