text stringlengths 0 2.2M |
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//..
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int usageExample1()
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{
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bslma::TestAllocator testAlloc;
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MyContainer<int> C1(123, &testAlloc);
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ASSERT(C1.allocator() == &testAlloc);
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ASSERT(C1.front() == 123);
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MyContainer<int> C2(C1);
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ASSERT(C2.allocator() == bslma::Default::defaultAllocator());
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ASSERT(C2.front() == 123);
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return 0;
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}
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//..
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//
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///Example 2: 'bslma' Allocator Propagation
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///- - - - - - - - - - - - - - - - - - - -
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// This example demonstrates that 'MyContainer' does indeed propagate the
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// allocator to its contained element.
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//
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// First, we create a representative element class, 'MyType', that allocates
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// memory using the 'bslma' allocator protocol:
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//..
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#include <bslma_default.h>
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class MyType {
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// DATA
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// ...
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bslma::Allocator *d_allocator_p;
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public:
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// TRAITS
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BSLMF_NESTED_TRAIT_DECLARATION(MyType, bslma::UsesBslmaAllocator);
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// CREATORS
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explicit MyType(bslma::Allocator *basicAllocator = 0)
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// Create a 'MyType' object having the default value. Optionally
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// specify a 'basicAllocator' used to supply memory. If
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// 'basicAllocator' is 0, the currently installed default allocator
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// is used.
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: d_allocator_p(bslma::Default::allocator(basicAllocator))
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{
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// ...
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}
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MyType(const MyType& original, bslma::Allocator *basicAllocator = 0)
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// Create a 'MyType' object having the same value as the specified
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// 'original' object. Optionally specify a 'basicAllocator' used
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// to supply memory. If 'basicAllocator' is 0, the currently
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// installed default allocator is used.
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: d_allocator_p(bslma::Default::allocator(basicAllocator))
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{
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(void) original;
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// ...
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}
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// ...
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// ACCESSORS
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bslma::Allocator *allocator() const
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// Return the allocator used by this object to supply memory.
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{
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return d_allocator_p;
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}
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// ...
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};
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//..
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// Finally, we instantiate 'MyContainer' using 'MyType' and verify that, when
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// we provide the address of an allocator to the constructor of the container,
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// the same address is passed to the constructor of the contained element. We
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// also verify that, when the container is copy-constructed without supplying
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// an allocator, the copy uses the default allocator, not the allocator from
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// the original object. Moreover, we verify that the element stored in the
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// copy also uses the default allocator:
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//..
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int usageExample2()
|
{
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bslma::TestAllocator testAlloc;
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MyContainer<MyType> C1(&testAlloc);
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ASSERT(C1.allocator() == &testAlloc);
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ASSERT(C1.front().allocator() == &testAlloc);
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MyContainer<MyType> C2(C1);
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ASSERT(C2.allocator() != C1.allocator());
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ASSERT(C2.allocator() == bslma::Default::defaultAllocator());
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ASSERT(C2.front().allocator() != &testAlloc);
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ASSERT(C2.front().allocator() == bslma::Default::defaultAllocator());
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return 0;
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}
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//..
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//
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#if defined(BSLS_COMPILERFEATURES_GUARANTEED_COPY_ELISION)
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///Example 3: Constructing into Non-heap Memory
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///- - - - - - - - - - - - - - - - - - - - - -
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// This example demonstrates using 'bslma::ConstructionUtil::make' to
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// implement a simple wrapper class that contains a single item that might or
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