Szabolcs NagyandRich Felker
d150764697
the linux man page specifies malloc_usable_size(0) to return 0 and this is the semantics other implementations follow (jemalloc). reported by Alexander Monakov.
18 lines
384 B
C
18 lines
384 B
C
#include <malloc.h>
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void *(*const __realloc_dep)(void *, size_t) = realloc;
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struct chunk {
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size_t psize, csize;
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struct chunk *next, *prev;
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};
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#define OVERHEAD (2*sizeof(size_t))
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#define CHUNK_SIZE(c) ((c)->csize & -2)
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#define MEM_TO_CHUNK(p) (struct chunk *)((char *)(p) - OVERHEAD)
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size_t malloc_usable_size(void *p)
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{
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return p ? CHUNK_SIZE(MEM_TO_CHUNK(p)) - OVERHEAD : 0;
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}
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