NAME
mallocusablesize - obtain size of block of memory allocated from heap SYNOPSIS
#include
sizet mallocusablesize (void *ptr); DESCRIPTION The mallocusablesize() 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. RETURN VALUE mallocusablesize() returns the number of usable bytes in the block of allocated memory pointed to by ptr. If ptr is NULL, 0 is returned. ATTRIBUTES For an explanation of the terms used in this section, see attributes(7). ┌─────────────────────┬───────────────┬─────────┐ │Interface │ Attribute │ Value │ ├─────────────────────┼───────────────┼─────────┤ │mallocusablesize() │ Thread safety │ MT-Safe │ └─────────────────────┴───────────────┴─────────┘ CONFORMING TO This function is a GNU extension. NOTES The value returned by mallocusablesize() 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. SEE ALSO malloc(3) COLOPHON
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GNU 2012-03-29 MALLOCUSABLESIZE(3)