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   malloc_usable_size    ( 3 )

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Имя (Name)

malloc_usable_size - obtain size of block of memory allocated
       from heap

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Синопсис (Synopsis)

#include <malloc.h>

       size_t malloc_usable_size(void *ptr);

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Описание (Description)

The malloc_usable_size() function returns the number of usable
       bytes in the block pointed to by ptr, a pointer to a block of
       memory allocated by malloc(3) or a related function.

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Возвращаемое значение (Return value)

malloc_usable_size() returns the number of usable bytes in the
       block of allocated memory pointed to by ptr.  If ptr is NULL, 0
       is returned.

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Атрибуты (Attributes)

For an explanation of the terms used in this section, see
       attributes(7).

       ┌──────────────────────────────────────┬───────────────┬─────────┐
       │Interface                             │ Attribute     │ Value   │
       ├──────────────────────────────────────┼───────────────┼─────────┤
       │malloc_usable_size()                  │ Thread safety │ MT-Safe │
       └──────────────────────────────────────┴───────────────┴─────────┘

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Стандарты (Conforming to)

This function is a GNU extension.

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Примечание (Note)

The value returned by malloc_usable_size() may be greater than
       the requested size of the allocation because of alignment and
       minimum size constraints.  Although the excess bytes can be
       overwritten by the application without ill effects, this is not
       good programming practice: the number of excess bytes in an
       allocation depends on the underlying implementation.

       The main use of this function is for debugging and introspection.

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Смотри также (See also)

malloc(3)

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