- Generated by
1.9.8
|
BDE 4.14.0 Production release
|
Modules | |
| bsls_alignedbuffer | |
| Provide raw buffers with user-specified size and alignment. | |
| bsls_alignment | |
| Provide a namespace for enumerating memory alignment strategies. | |
| bsls_alignmentfromtype | |
Provide a meta-function that maps a TYPE to its alignment. | |
| bsls_alignmentimp | |
| Provide implementation meta-functions for alignment computation. | |
| bsls_alignmenttotype | |
Provide a meta-function mapping an ALIGNMENT to a primitive type. | |
| bsls_alignmentutil | |
| Provide constants, types, and operations related to alignment. | |
| bsls_annotation | |
| Provide support for compiler annotations for compile-time safety. | |
| bsls_assert | |
| Provide build-specific, runtime-configurable assertion macros. | |
| bsls_assert_macroreset | |
Undefine all macros from bsls_assert.h and bsls_review.h. | |
| bsls_assertimputil | |
Provide utilities to implement bsls_assert and bsls_review. | |
| bsls_asserttest | |
| Provide a test facility for assertion macros. | |
| bsls_asserttest_macroreset | |
Undefine macros related to bsls_asserttest.h. | |
| bsls_asserttestexception | |
| Provide an exception type to support testing for failed assertions. | |
| bsls_atomic | |
| Provide types with atomic operations. | |
| bsls_atomicoperations | |
| Provide platform-independent atomic operations. | |
| bsls_atomicoperations_all_all_clangintrinsics | |
Implement atomic operations using clang __c11_atomic_* intrinsics. | |
| bsls_atomicoperations_all_all_gccintrinsics | |
Implement atomic operations using gcc __atomic_* intrinsics. | |
| bsls_atomicoperations_arm32_win_msvc | |
| Provide implementations of atomic operations for arm32/MSVC/Win. | |
| bsls_atomicoperations_arm64_win_msvc | |
| Provide implementations of atomic operations for arm64/MSVC/Win. | |
| bsls_atomicoperations_arm_all_gcc | |
| Provide implementations of atomic operations for ARM/GCC. | |
| bsls_atomicoperations_default | |
| Provide default implementation for atomic operations. | |
| bsls_atomicoperations_powerpc32_aix_xlc | |
| Provide implementations of atomic operations for PowerPC/AIX-32bit. | |
| bsls_atomicoperations_powerpc64_aix_xlc | |
| Provide implementations of atomic operations for PowerPC/AIX-64bit. | |
| bsls_atomicoperations_powerpc_aix_xlc_default | |
| Provide default base implementations of atomics for PowerPC/AIX. | |
| bsls_atomicoperations_powerpc_all_gcc | |
| Provide implementations of atomic operations for gcc on PowerPC. | |
| bsls_atomicoperations_sparc32_sun_cc | |
| Provide implementations of atomic operations for Sparc/Sun (32bit). | |
| bsls_atomicoperations_sparc64_sun_cc | |
| Provide implementations of atomic operations for Sparc/Sun (64bit). | |
| bsls_atomicoperations_sparc_sun_cc_default | |
| Provide default base implementations of atomics for Sparc/Sun. | |
| bsls_atomicoperations_x64_all_gcc | |
| Provide implementations of atomic operations for X86_64/GCC. | |
| bsls_atomicoperations_x64_win_msvc | |
| Provide implementations of atomic operations for X86_64/MSVC/Win64. | |
| bsls_atomicoperations_x86_all_gcc | |
| Provide implementations of atomic operations for X86/GCC. | |
| bsls_atomicoperations_x86_win_msvc | |
| Provide implementations of atomic operations for X86/MSVC/Windows. | |
| bsls_blockgrowth | |
| Provide a namespace for memory block growth strategies. | |
| bsls_bsldeprecationinformation | |
Provide a macro to control bsl deprecations by release version. | |
| bsls_bslexceptionutil | |
Provide functions for use in bsl that throw standard exceptions. | |
| bsls_bsllock | |
Provide a platform-independent mutex for use below bslmt. | |
| bsls_bsllockimpl_pthread | |
Provide a mutex for use below bslmt. | |
| bsls_bsllockimpl_win32 | |
Provide a mutex for use below bslmt for windows platform. | |
| bsls_bslonce | |
| Provide BSL a thread-safe way to execute code once per process. | |
| bsls_bslsourcenameparserutil | |
| Provide low-level functions for parsing source file names. | |
| bsls_bsltestutil | |
Provide test utilities for bsl that do not use <iostream>. | |
| bsls_buildtarget | |
| Provide build-target information in object files. | |
| bsls_byteorder | |
| Provide byte-order manipulation macros. | |
| bsls_byteorderutil | |
| Provide byte-order swapping functions. | |
| bsls_byteorderutil_impl | |
| Provide implementation of byte-order manipulation functions. | |
| bsls_compilerfeatures | |
| Provide macros to identify compiler support for C++11 features. | |
| bsls_consteval | |
| Provide macros related to compile-time evaluation. | |
| bsls_cpp11 | |
| Provide macros for C++11 forward compatibility. | |
| bsls_deprecate | |
| Provide machinery to deprecate interfaces on a per-version basis. | |
| bsls_deprecatefeature | |
| Provide machinery to deprecate entities in C++ code. | |
| bsls_exceptionutil | |
| Provide simplified exception constructs for non-exception builds. | |
| bsls_fuzztest | |
| Provide macros for use in fuzz testing narrow-contract functions. | |
| bsls_fuzztestpreconditionexception | |
| Provide an exception type for handling failed preconditions. | |
| bsls_ident | |
| Provide macros for inserting SCM Ids into source files. | |
| bsls_int64 | |
| Provide namespace for platform-dependent 64-bit integer types. | |
| bsls_keyword | |
| Provide macros for forward language dialect compatibility. | |
| bsls_libraryfeatures | |
| Provide macros to identify native standard library features. | |
| bsls_linkcoercion | |
| Provide a way to force a link-time dependency into an object. | |
| bsls_log | |
| Provide a namespace for low-level logging functions. | |
| bsls_logseverity | |
| Enumerate a set of logging severity levels. | |
| bsls_macroincrement | |
| Provide a macro to increment preprocessor numbers. | |
| bsls_macrorepeat | |
| repeat a macro invocation with different numeric arguments. | |
| bsls_nameof | |
Provide a NameOf type for displaying template type at run-time. | |
| bsls_nativestd | |
Define the namespace native_std as an alias for std. | |
| bsls_nullptr | |
| Provide a distinct type for null pointer literals. | |
| bsls_objectbuffer | |
| Provide raw buffer with size and alignment of user-specified type. | |
| bsls_outputredirector | |
| Provide a means for test drivers to redirect and inspect output. | |
| bsls_performancehint | |
| Provide performance hints for code optimization. | |
| bsls_platform | |
| Provide compile-time support for platform/attribute identification. | |
| bsls_platformutil | |
| Provide consistent interface for platform-dependent functionality. | |
| bsls_pointercastutil | |
| Provide function to cast between function and data pointers. | |
| bsls_preconditions | |
| Provide macros for use in fuzz testing narrow contract functions. | |
| bsls_protocoltest | |
| Provide classes and macros for testing abstract protocols. | |
| bsls_review | |
| Provide assertion macros to safely identify contract violations. | |
| bsls_review_macroreset | |
Test driver utility to undefine all macros from bsls_review.h. | |
| bsls_spinlock | |
| Provide a spin lock. | |
| bsls_stackaddressutil | |
| Provide a utility for obtaining return addresses from the stack. | |
| bsls_stackaddressutil_plinktimestamp | |
Declare and weakly define a plink_timestamp___ global variable. | |
| bsls_stopwatch | |
| Provide access to user, system, and wall times of current process. | |
| bsls_systemclocktype | |
| Enumerate the set of system clock types. | |
| bsls_systemtime | |
| Provide utilities to retrieve the system time. | |
| bsls_timeinterval | |
| Provide a representation of a time interval. | |
| bsls_timeutil | |
| Provide a platform-neutral functional interface to system clocks. | |
| bsls_types | |
| Provide a consistent interface for platform-dependent types. | |
| bsls_unspecifiedbool | |
Provide a class supporting the unspecified bool idiom. | |
| bsls_util | |
| Provide essential, low-level support for portable generic code. | |
Provide system-level utilities for 'bsl'.
Basic Standard Library System utilities (bsls)
The 'bsls' package provides a variety of system utilities for use by the 'bsl' library. These utilities include:
Note that the above list is not meant to be exhaustive. The sections below provide more information about the individual components.
The 'bsls' package currently has 86 components having 16 levels of physical dependency. The list below shows the hierarchical ordering of the components. The order of components within each level is not architecturally significant, just alphabetical.
bsls_alignedbuffer : Provide raw buffers with user-specified size and alignment.
bsls_alignment : Provide a namespace for enumerating memory alignment strategies.
bsls_alignmentfromtype : Provide a meta-function that maps a TYPE to its alignment.
bsls_alignmentimp : Provide implementation meta-functions for alignment computation.
bsls_alignmenttotype : Provide a meta-function mapping an ALIGNMENT to a primitive type.
bsls_alignmentutil : Provide constants, types, and operations related to alignment.
bsls_annotation : !DEPRECATED! Provide support for compiler annotations for compile-time safety.
bsls_assert : Provide build-specific, runtime-configurable assertion macros.
'bsls_assert_macroreset': !PRIVATE! Undefine all macros from bsls_assert.h and bsls_review.h.
bsls_assertimputil : Provide utilities to implement bsls_assert and bsls_review .
bsls_asserttest : Provide a test facility for assertion macros.
'bsls_asserttest_macroreset': !PRIVATE! Undefine macros related to bsls_asserttest.h.
bsls_asserttestexception : Provide an exception type to support testing for failed assertions.
bsls_atomic : Provide types with atomic operations.
bsls_atomicoperations : Provide platform-independent atomic operations.
'bsls_atomicoperations_all_all_clangintrinsics': !PRIVATE! Implement atomic operations using clang __c11_atomic_* intrinsics
'bsls_atomicoperations_all_all_gccintrinsics': !PRIVATE! Implement atomic operations using gcc __atomic_* intrinsics.
'bsls_atomicoperations_arm32_win_msvc': !PRIVATE! Provide implementations of atomic operations for arm32/MSVC/Win.
'bsls_atomicoperations_arm64_win_msvc': !PRIVATE! Provide implementations of atomic operations for arm64/MSVC/Win.
'bsls_atomicoperations_arm_all_gcc': !PRIVATE! Provide implementations of atomic operations for ARM/GCC.
'bsls_atomicoperations_default': !PRIVATE! Provide default implementation for atomic operations.
'bsls_atomicoperations_powerpc32_aix_xlc': !PRIVATE! Provide implementations of atomic operations for PowerPC/AIX-32bit.
'bsls_atomicoperations_powerpc64_aix_xlc': !PRIVATE! Provide implementations of atomic operations for PowerPC/AIX-64bit.
'bsls_atomicoperations_powerpc_aix_xlc_default': !PRIVATE! Provide default base implementations of atomics for PowerPC/AIX.
'bsls_atomicoperations_powerpc_all_gcc': !PRIVATE! Provide implementations of atomic operations for gcc on PowerPC
'bsls_atomicoperations_sparc32_sun_cc': !PRIVATE! Provide implementations of atomic operations for Sparc/Sun (32bit).
'bsls_atomicoperations_sparc64_sun_cc': !PRIVATE! Provide implementations of atomic operations for Sparc/Sun (64bit).
'bsls_atomicoperations_sparc_sun_cc_default': !PRIVATE! Provide default base implementations of atomics for Sparc/Sun.
'bsls_atomicoperations_x64_all_gcc': !PRIVATE! Provide implementations of atomic operations for X86_64/GCC.
'bsls_atomicoperations_x64_win_msvc': !PRIVATE! Provide implementations of atomic operations for X86_64/MSVC/Win64.
'bsls_atomicoperations_x86_all_gcc': !PRIVATE! Provide implementations of atomic operations for X86/GCC.
'bsls_atomicoperations_x86_win_msvc': !PRIVATE! Provide implementations of atomic operations for X86/MSVC/Windows.
bsls_blockgrowth : Provide a namespace for memory block growth strategies.
bsls_bsldeprecationinformation : Provide a macro to control bsl deprecations by release version.
bsls_bslexceptionutil : Provide functions for use in bsl that throw standard exceptions.
bsls_bsllock : Provide a platform-independent mutex for use below bslmt.
'bsls_bsllockimpl_pthread': !PRIVATE! Provide a mutex for use below bslmt.
'bsls_bsllockimpl_win32': !PRIVATE! Provide a mutex for use below bslmt for windows platform.
bsls_bslonce : Provide BSL a thread-safe way to execute code once per process.
bsls_bslsourcenameparserutil : Provide low-level functions for parsing source file names.
bsls_bsltestutil : Provide test utilities for bsl that do not use <iostream>.
bsls_buildtarget : Provide build-target information in object files.
bsls_byteorder : Provide byte-order manipulation macros.
bsls_byteorderutil : Provide byte-order swapping functions.
'bsls_byteorderutil_impl': !PRIVATE! Provide implementation of byte-order manipulation functions.
bsls_compilerfeatures : Provide macros to identify compiler support for C++11 features.
bsls_consteval : Provide macros related to compile-time evaluation.
bsls_cpp11 : !DEPRECATED! Provide macros for C++11 forward compatibility.
bsls_deprecate : !DEPRECATED! Provide machinery to deprecate interfaces on a per-version basis.
bsls_deprecatefeature : Provide machinery to deprecate entities in C++ code.
bsls_exceptionutil : Provide simplified exception constructs for non-exception builds.
bsls_fuzztest : Provide macros for use in fuzz testing narrow-contract functions.
bsls_fuzztestpreconditionexception : Provide an exception type for handling failed preconditions.
bsls_ident : Provide macros for inserting SCM Ids into source files.
bsls_int64 : !DEPRECATED! Provide namespace for platform-dependent 64-bit integer types.
bsls_keyword : Provide macros for forward language dialect compatibility.
bsls_libraryfeatures : Provide macros to identify native standard library features.
bsls_linkcoercion : Provide a way to force a link-time dependency into an object.
'bsls_log': Provide a namespace for low-level logging functions.
bsls_logseverity : Enumerate a set of logging severity levels.
bsls_macroincrement : Provide a macro to increment preprocessor numbers.
bsls_macrorepeat : repeat a macro invocation with different numeric arguments.
bsls_nameof : Provide a NameOf type for displaying template type at run-time.
bsls_nativestd : !DEPRECATED! Define the namespace native_std as an alias for std.
bsls_nullptr : Provide a distinct type for null pointer literals.
bsls_objectbuffer : Provide raw buffer with size and alignment of user-specified type.
bsls_outputredirector : Provide a means for test drivers to redirect and inspect output.
bsls_performancehint : Provide performance hints for code optimization.
bsls_platform : Provide compile-time support for platform/attribute identification.
bsls_platformutil : !DEPRECATED! Provide consistent interface for platform-dependent functionality.
bsls_pointercastutil : Provide function to cast between function and data pointers.
bsls_preconditions : Provide macros for use in fuzz testing narrow contract functions.
bsls_protocoltest : Provide classes and macros for testing abstract protocols.
bsls_review : Provide assertion macros to safely identify contract violations.
'bsls_review_macroreset': !PRIVATE! Test driver utility to undefine all macros from bsls_review.h.
bsls_spinlock : Provide a spin lock.
bsls_stackaddressutil : Provide a utility for obtaining return addresses from the stack.
'bsls_stackaddressutil_plinktimestamp': !PRIVATE! Declare and weakly define a plink_timestamp___ global variable.
bsls_stopwatch : Provide access to user, system, and wall times of current process.
bsls_systemclocktype : Enumerate the set of system clock types.
bsls_systemtime : Provide utilities to retrieve the system time.
bsls_timeinterval : Provide a representation of a time interval.
bsls_timeutil : Provide a platform-neutral functional interface to system clocks.
bsls_types : Provide a consistent interface for platform-dependent types.
bsls_unspecifiedbool : Provide a class supporting the unspecified bool idiom.
bsls_util : Provide essential, low-level support for portable generic code.
This section provides a brief introduction to some of the components in the 'bsls' package. See the documentation in each component for full details.
The {bsls_alignedbuffer } component provides a parameterized buffer type with a user-specified compile-time size and user-specified alignment. Typically, such a type is used in situations where it is desirable to allocate a block of properly-aligned raw memory from somewhere other than the heap, e.g., on the stack or within an aggregate object, including within a union. It is a convenient way to create a small heap from which one or more objects are allocated at run-time.
The {bsls_alignment } component computes (at compile-time) platform-dependent alignment information. This component also provides a namespace for a suite of compile-time constants and pure procedures that yield platform-dependent alignment information for primitive and user-defined types, including the maximum alignment for any type and the smallest fundamental type requiring maximum alignment. These functions, used in conjunction, are especially useful for creating pools and allocators that rely on efficient alignment.
The {bsls_alignmentfromtype } component provides a meta-function that provides the alignment for a 'TYPE' template parameter.
The {bsls_alignmentimp } component provides a suite of template meta-functions that can be used to compute (at compile-time) various platform-dependent alignment information.
The {bsls_alignmenttotype } component provides a meta-function that defines a primitive type with an alignment matching a 'ALIGNMENT' template parameter.
The {bsls_alignmentutil } component provides a suite of template meta-functions that can be used to compute (at compile-time) various platform-dependent alignment information.
The {bsls_annotation } component provides a suite of preprocessor macros that define compiler-specific compile-time annotations.
The {bsls_assert } component provides a set of "assert-like" macros to implement a compile-time-selectable and run-time-configurable "defensive" or "safe" mode. It also provides a suite of "assert-failure handler" methods suitable for runtime loading into the macros, via also provided methods. Users may supply their own handler methods matching the proper signature. To allow the user more flexibility in changing handlers during program execution, this component also provides a scoped guard that allows safe, temporary changing of the failure handler in a limited scope.
The {bsls_asserttest } component provides a facility to test that 'BSLS_ASSERT_*' macros are used as intended, in the appropriate build modes, and have the expected effects.
The {bsls_asserttestexception } component implements an exception class, 'bsls::AssertTestException', that provides a mechanism to convey context information from a failing assertion to a test handler.
The {bsls_atomic } component provides classes with atomic operations for 'int', 'Int64', and pointer types.
The {bsls_atomicoperations } component provides a set of platform-independent atomic operations for fundamental data types, such as 32-bit and 64-bit integer and pointer.
The {bsls_blockgrowth } component enumerates the supported block growth strategies.
The {bsls_bsltestutil } component provides the standard printing macros used in BDE-style test drivers.
The {bsls_buildtarget } component defines types and runtime constants for identifying the build target information (usually specified to the compiler via a set of 'BDE_BUILD_*' macros). This is mostly useful for retrieving such information from a linkable or executable binary.
The {bsls_byteorder } component provides a set host-to-network and network-to-host byte-order manipulation macros.
The {bsls_compilerfeatures } component provides a suite of preprocessor macros to identify compiler-specific support of language features that may not be available on all compilers in use across an organization.
The {bsls_deprecate } component provides a suite of macros to control (on a per-version, per-UOR basis) the deprecation of functions, user-defined types, and 'typedef's.
The {bsls_exceptionutil } component provides macros to replace 'try', 'throw' and 'catch'. These macros expand to normal exception constructs when exceptions are enabled and to reasonable alternatives (usually no-ops) when exceptions are disabled, allowing code that uses 'try', 'throw' and 'catch' constructs to compile even if exceptions are disabled using a compiler switch.
The {bsls_ident } component provides macros for inserting SCM (Source Control Management) Ids into source files.
The {bsls_macroincrement } component provides a macro, 'BSLS_MACROINCREMENT(NUMBER)', that produces the preprocessor number equal to the number succeeding the supplied argument.
The {bsls_nativestd } component defines a namespace alias, 'native_std', that serves as an alias for the 'std' namespace.
The {bsls_nullptr } component provides a limited emulation of the C++11 type, 'std::nullptr_t', which can be used as a function parameter type to create an overload set where null pointer literals are handled specially.
The {bsls_objectbuffer } component provides a parameterized buffer type, 'bsls_ObjectBuffer', which is compile-time sized and aligned to hold a specified object type. Defining a 'bsls_ObjectBuffer<T>' object does not cause the constructor for 'T' to be called. Similarly, destroying the object buffer does not call the destructor for 'T'. Typically, a 'bsls_ObjectBuffer' is used in situations where efficient (e.g., stack-based) storage is required but where straightforward initialization or destruction of an object is not possible. It can also be used to create a 'union' containing non-POD element types.
The {bsls_performancehint } component provides performance hints for the compiler or hardware.
The {bsls_platform } component defines preprocessor macros that identify and describe platform-specific attributes (at compile time). These attributes consist of the types and versions of operating system, processor(s), and compiler that comprise the platform.
The {bsls_protocoltest } component provides classes and macros for testing abstract protocols.
The {bsls_stopwatch } component implements a real-time (system clock) interval timer. A 'bsls_Stopwatch' object can accumulate and return only one interval at a time, but may be started and stopped repeatedly without being reset, so the elapsed time "interval" accumulated by a single object may be from multiple, discontinuous segments of time. The non-negative total accumulated time (in seconds) is available as a 'double' value.
The {bsls_systemclocktype } component provides a namespace for the 'enum' type 'bsls::SystemClockType::Enum', which enumerates the set of system clock types. A 'bsls::SystemClockType' is particularly important when providing time-out values to synchronization methods where those time-outs must be consistent in environments where the system clocks may be changed.
The {bsls_timeutil } component provides a set of platform-neutral pure procedures to access real-time system clock functionality. High-resolution time functions intended for interval-timing return an interval in nanoseconds (1 nsec = 1E-9 sec) as a 64-bit integer.
The {bsls_types } component provides a namespace for a set of 'typedef's that provide a stable, portable interface to platform-dependent types.
The {bsls_unspecifiedbool } component provides a class template that can be used to manufacture an "unspecified boolean type" that is distinct for each class that instantiates it. Not for use outside the 'bsl' package.
The {bsls_util } component provides pure functions that supply essential low-level support for implementing portable generic facilities such as might be found in the C++ standard library.
Modern C++ (C++11 and later) introduces the concepts of moving and forwarding function arguments. The BDE library provides facilities to replicate these features in C++03, and also allow writing code in a way that the same code can be compiled in both C++03 and in modern C++ (where the features are natively supported). This document describes which of these BDE facilities to use in which contexts. This section assumes familiarity with movable types and the use of {bslmf_movableref } for move semantics in C++03-compatible code.
Four utilities are to be described and their correct usage explained, and they are summarized in the following table. The term "forwarding" refers to passing a variable recieved as an argument in one function to another function, generally without altering it. The term "perfect forwarding" refers to forwarding not only the value that the argument represents, but also characterstics of the argument such as cv-qualifications, and whether it is an rvalue or an lvalue.
'BSLS_COMPILERFEATURES_FORWARD_REF(T)': Used to declare a function template argument of type 'T' that is to be perfect-forwarded. 'BSLS_COMPILERFEATURES_FORWARD(T, V)': Used to perfect-forward a function template argument, 'V', of type 'T'. 'BSLMF_MOVABLEREF_DEDUCE(T)': Used to deduce the type 'T' of a templated rvalue reference argument. 'bslmf::ForwardingType' and 'bslmf::ForwardingRefType': Used to forward arguments through layers of nested calls efficiently.
The following sections explain in detail the contexts in which the above macros and types are used.
In modern C++, function parameters marked with double ampersands ('&&') can either be movable references or forwarding references. The difference is whether the type of the parameter excluding the '&&' is a template type of the function (templates are forwarding references, non-templates are movable references). Forwarding references are lvalues that can bind to either an lvalue reference or an rvalue reference, and can be converted back to the original reference type with 'bsl::forward'. The BDE library achieves this effect in C++03 with two macros, 'BSLS_COMPILERFEATURES_FORWARD_REF' and 'BSLS_COMPILERFEATURES_FORWARD'.
'BSLS_COMPILERFEATURES_FORWARD_REF(T)' is used to declare a function template argument of type 'T' that is to be perfect-forwarded.
'BSLS_COMPILERFEATURES_FORWARD(T, V)' is used to perfect-forward a function template argument, 'V', of type 'T'.
For example:
The following code will compile and run in any BDE-supported version of C++.
This program should output the following.
'bslmf::MovableRef' is a template facility that provides move semantics in C++03. One common issue with 'MovableRef<T>' is its use in a context where 'T' itself is a template parameter: the compiler will be unable to deduce the type of 'T' in C++11 (or later) as one would expect. For example:
To deduce this type, the macro 'BSLMF_MOVABLEREF_DEDUCE' can be used, for example:
A real world example can be found in component {bdlb_nullablevalue }. The 'bdlb::NullableValue<TYPE>' constructor taking a movable reference to a 'bdlb::NullableValue<BDE_OTHER_TYPE>', with 'BDE_OTHER_TYPE' convertible to 'TYPE', uses 'BSLMF_MOVABLEREF_DEDUCE'.
Generic code that forwards arguments through many layers of metaprogramming templates – e.g., 'bsl::function' and 'bsl::bind' – can be made more efficient through judicious use of 'bslmf::ForwardingRefType'. This allows a number of small optimizations. For example, the collapse of array references to pointers that are unpacked only once, thereby reducing the number of template instantiations of the middle layers. The older 'bslmf::ForwardingType' served the same purpose, but is no longer recommended since 'bslmf::ForwardingRefType' is simpler to use.
Note: The component bslmf_forwardingreftype is a complex tool with a singular purpose, and occassions for its legitimate use are rare.
1.9.8