The C11 standard has enhanced the allocator interface to allow 'scoped' allocators, so that containers with 'nested' memory allocations, such as vector of strings or a map of lists of sets of user-defined types, can ensure that all memory is sourced from the container's allocator. May 06, 1998 Avoid Using malloc and free in C The use of malloc and free functions in a C file is not recommended and is even dangerous: 1. Malloc requires the exact number of bytes as an argument whereas new calculates the size of the allocated object automatically.
-->
This document shows how to use the concurrency::Alloc and concurrency::Free functions to improve memory performance. It compares the time that is required to reverse the elements of an array in parallel for three different types that each specify the
new and delete operators.
The
Alloc and Free functions are most useful when multiple threads frequently call both Alloc and Free . The runtime holds a separate memory cache for each thread; therefore, the runtime manages memory without the use of locks or memory barriers.
Example
The following example shows three types that each specify the
new and delete operators. The new_delete class uses the global new and delete operators, the malloc_free class uses the C Runtime malloc and free functions, and the Alloc_Free class uses the Concurrency Runtime Alloc and Free functions.
Example
The following example shows the
swap and reverse_array functions. The swap function exchanges the contents of the array at the specified indices. It allocates memory from the heap for the temporary variable. The reverse_array function creates a large array and computes the time that is required to reverse that array several times in parallel.
Vocal tuning has never been easier or more precise. The ultimate pitch correction tool, for perfectly tuned natural-sounding vocals or creative effects. Better-sounding and more versatile than any other pitch correction processor, Waves Tune will get your vocals back on track. Live auto tune logic. With an extensive palette of pitch shaping and transformation tools, including full ReWire support and formant correction, Waves Tune lets you do all your pitch editing right there within your DAW environment – no need to export sections or work offline.
Example
The following example shows the
wmain function, which computes the time that is required for the reverse_array function to act on the new_delete , malloc_free , and Alloc_Free types, each of which uses a different memory allocation scheme.
ExampleMalloc Vs Alloc
The complete example follows.
This example produces the following sample output for a computer that has four processors.
In this example, the type that uses the
Alloc and Free functions provides the best memory performance because the Alloc and Free functions are optimized for frequently allocating and freeing blocks of memory from multiple threads.
Compiling the Code
Copy the example code and paste it in a Visual Studio project, or paste it in a file that is named
allocators.cpp and then run the following command in a Visual Studio Command Prompt window.
How To Use Malloc In Dev C++
cl.exe /EHsc allocators.cpp
See also
Memory Management Functions
Alloc Function Free Function Using Malloc In Dev C++
Comments are closed.
|
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |