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\page PageLibsMysqlAllocators Library: Allocators

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Code documentation: @ref GroupLibsMysqlAllocators.

Summary

Allows libraries to allocate memory such that:

• The server can use the library in such a way that the memory is performance_schema-instrumented.
• Other code can use the library without performance_schema instrumentation.
• The library is never dependent on performance_schema.

Usage

This library provides the Memory_resource and Allocator classes, which are used in different ways depending on who you are:

• Library author: If your library needs to allocate memory, add a Memory_resource parameter to either the function that allocates memory or the constructor for the class that manages the memory. The parameter must be passed by value, not reference or pointer. Allocate memory through an Allocator based on this object. Make the parameter default to Memory_resource().

• Library user within the MySQL server: When using the function or class that takes a Memory_resource object, call psi_memory_resource(Psi_memory_key) to get the Memory_resource object to pass to the function or constructor.

• Library user outside the MySQL server: When using the function or class constructor that takes an optional Memory_resource parameter, allow that parameter to take its default value.