memcached_set_memory_allocators - Man Page

Name

memcached_set_memory_allocators — libmemcached Documentation

Manage memory allocator functions

Synopsis

#include <libmemcached/memcached.h>

Compile and link with -lmemcached

memcached_return_t memcached_set_memory_allocators(memcached_st *ptr, memcached_malloc_fn mem_malloc, memcached_free_fn mem_free, memcached_realloc_fn mem_realloc, memcached_calloc_fn mem_calloc, void *context)
Parameters
  • ptr -- pointer to an initialized memcached_st struct
  • mem_malloc -- pointer to a memcached_malloc_fn callback
  • mem_free -- pointer to a memcached_free_fn callback
  • mem_realloc -- pointer to a memcached_realloc_fn callback
  • mem_calloc -- pointer to a memcached_calloc_fn callback
  • context -- pointer to a user supplied context
Returns

memcached_return_t indicating success

void memcached_get_memory_allocators(memcached_st *ptr, memcached_malloc_fn *mem_malloc, memcached_free_fn *mem_free, memcached_realloc_fn *mem_realloc, memcached_calloc_fn *mem_calloc)
Parameters
  • ptr -- pointer to an initialized memcached_st struct
  • mem_malloc -- pointer to store the address of the memcached_malloc_fn callback
  • mem_free -- pointer to store the address of the memcached_free_fn callback
  • mem_realloc -- pointer to store the address of the memcached_realloc_fn callback
  • mem_calloc -- pointer to store the address of the memcached_calloc_fn callback
void *memcached_get_memory_allocators_context(const memcached_st *ptr)
Parameters

ptr -- pointer to an initialized memcached_st struct

Returns

pointer to the user supplied context

typedef void *(*memcached_malloc_fn)(memcached_st *ptr, const size_t size, void *context)
Parameters
  • ptr -- pointer to an initialized memcached_st struct
  • size -- the number of bytes to allocate
  • context -- pointer to the user supplied context
Returns

pointer to at least size bytes of allocated memory

typedef void *(*memcached_realloc_fn)(memcached_st *ptr, void *mem, const size_t size, void *context)
Parameters
  • ptr -- pointer to an initialized memcached_st struct
  • mem -- pointer to previously allocated memory
  • size -- the number of bytes to allocate
  • context -- pointer to the user supplied context
Returns

pointer to at least size bytes of allocated memory

typedef void (*memcached_free_fn)(memcached_st *ptr, void *mem, void *context)
Parameters
  • ptr -- pointer to an initialized memcached_st struct
  • mem -- pointer to previously allocated memory
  • context -- pointer to the user supplied context
typedef void *(*memcached_calloc_fn)(memcached_st *ptr, size_t nelem, const size_t elsize, void *context)
Parameters
  • ptr -- pointer to an initialized memcached_st struct
  • nelem -- number of elements to allocate
  • elsize -- the number of bytes to allocate per element
  • context -- pointer to the user supplied context
Returns

pointer to at least elsize * nelem  bytes of allocated and zeroed memory

Description

libmemcached allows you to specify your own memory allocators, optimized for your application. This enables libmemcached to be used inside of applications that have their own malloc implementation.

memcached_set_memory_allocators() is used to set the memory allocators used by the memcached instance specified by ptr. Please note that you cannot override only one of the memory allocators, you have to specify a complete new set if you want to override one of them. All of the memory allocation functions should behave as specified in the C99 standard. Specify NULL as all functions to reset them to the default values.

memcached_get_memory_allocators() is used to get the currently used memory allocators by a memcached handle.

memcached_get_memory_allocators_context() returns the void * that was passed in during the call to memcached_set_memory_allocators().

The first argument to the memory allocator functions is a pointer to a memcached structure, the is passed as const and you will need to clone it in order to make use of any operation which would modify it.

Notes

In version 0.38 all functions were modified to have a context void pointer passed to them. This was so that custom allocators could have their own space for memory.

Return Value

memcached_set_memory_allocators() returns MEMCACHED_SUCCESS upon success, and MEMCACHED_FAILURE if you don't pass a complete set of function pointers.

See Also

memcached(1) libmemcached(3) memcached_strerror(3)

Info

Sep 20, 2021 1.1 libmemcached-awesome