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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ATTRIBUTES | STANDARDS | NOTES | SEE ALSO |
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malloc_usable_size(3) Library Functions Manual malloc_usable_size(3)
malloc_usable_size - obtain size of block of memory allocated
from heap
Standard C library (libc, -lc)
#include <malloc.h>
size_t malloc_usable_size(void *ptr);
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.
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.
For an explanation of the terms used in this section, see
attributes(7).
┌──────────────────────────────────────┬───────────────┬─────────┐
│Interface │ Attribute │ Value │
├──────────────────────────────────────┼───────────────┼─────────┤
│malloc_usable_size() │ Thread safety │ MT-Safe │
└──────────────────────────────────────┴───────────────┴─────────┘
GNU.
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.
malloc(3)
Linux man-pages 6.04 2023-03-30 malloc_usable_size(3)
Pages that refer to this page: malloc(3)
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HTML rendering created 2023-06-24 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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