diff options
Diffstat (limited to 'lib/libc/stdlib/malloc.3')
| -rw-r--r-- | lib/libc/stdlib/malloc.3 | 27 |
1 files changed, 25 insertions, 2 deletions
diff --git a/lib/libc/stdlib/malloc.3 b/lib/libc/stdlib/malloc.3 index 9a888c5..46ce26c 100644 --- a/lib/libc/stdlib/malloc.3 +++ b/lib/libc/stdlib/malloc.3 @@ -32,11 +32,11 @@ .\" @(#)malloc.3 8.1 (Berkeley) 6/4/93 .\" $FreeBSD$ .\" -.Dd March 9, 2006 +.Dd March 28, 2006 .Dt MALLOC 3 .Os .Sh NAME -.Nm malloc , calloc , realloc , free , reallocf +.Nm malloc , calloc , realloc , free , reallocf , malloc_usable_size .Nd general purpose memory allocation functions .Sh LIBRARY .Lb libc @@ -58,6 +58,9 @@ .Fo \*(lp*_malloc_message\*(rp .Fa "const char *p1" "const char *p2" "const char *p3" "const char *p4" .Fc +.In malloc_np.h +.Ft size_t +.Fn malloc_usable_size "const void *ptr" .Sh DESCRIPTION The .Fn malloc @@ -133,6 +136,21 @@ If is .Dv NULL , no action occurs. +.Pp +The +.Fn malloc_usable_size +function returns the usable size of the allocation pointed to by +.Fa ptr . +The return value may be larger than the size that was requested during +allocation. +.Fn malloc_usable_size +is not a mechanism for in-place +.Fn realloc ; +rather it is provided soley as a tool for introspection purposes. +Any discrepancy between the requested allocation size and the size reported by +.Fn malloc_usable_size +should not be depended on, since such behavior is entirely +implementation-dependent. .Sh TUNING Once, when the first call is made to one of these memory allocation routines, various flags will be set or reset, which affect the @@ -443,3 +461,8 @@ The .Fn reallocf function first appeared in .Fx 3.0 . +.Pp +The +.Fn malloc_usable_size +function first appeared in +.Fx 7.0 . |
