Exit Zen
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The function <<ref_get_null_resource>> returns a global instance of the null resource. This resource offers a simple invariant: all calls to allocate will throw the exception `std::bad_alloc`. An instance of the null resource can be used to make parsing guarantee that allocations from the heap are never made. This is explored in more detail in a later section.
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`std::getline` use (see the warning in <<non_standard_json>> section).
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<<parse_numbers_json,*numbers.json*>>
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The result is equal to the result of `path::generic_string`.
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Supported Compilers
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<<ref_value_if_uint64>>
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Allocator Propagation
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We can complicate the example further by extracting _several_ JSON values from the sequence of lines.
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147KB
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The result is constructed from two pointers to `const char`.
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Boost.JSON has been tested with the following compilers:
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<<ref_value_try_as_uint64>>
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The containers <<ref_array>>, <<ref_object>>, and <<ref_value>> all propagate the memory resource they were constructed with to child elements:
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Controlling Memory
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A array containing only floating-point numbers.
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For composite types (sequences, tuples, described classes, etc.) conversion of contained objects is applied recursively. For example:
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clang: 3.5, 3.6, 3.7, 3.8, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14
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<<ref_value_as_uint64>>
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This propagation acts recursively, containers within containers will all have the resource propagated. Once a container is constructed, its memory resource can never be changed.
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After default construction, or after <<ref_stream_parser_reset>> is called with no arguments, the <<ref_value>> produced after a successful parse operation uses the default memory resource. To use a different memory resource, call `reset` with the resource to use. Here we use a <<ref_monotonic_resource>>, which is optimized for parsing but not subsequent modification:
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