diff options
Diffstat (limited to 'lib/libc/stdlib')
| -rw-r--r-- | lib/libc/stdlib/Makefile.inc | 2 | ||||
| -rw-r--r-- | lib/libc/stdlib/Symbol.map | 1 | ||||
| -rw-r--r-- | lib/libc/stdlib/malloc.3 | 27 | ||||
| -rw-r--r-- | lib/libc/stdlib/malloc.c | 20 |
4 files changed, 47 insertions, 3 deletions
diff --git a/lib/libc/stdlib/Makefile.inc b/lib/libc/stdlib/Makefile.inc index 27eee7d..99ea7fb 100644 --- a/lib/libc/stdlib/Makefile.inc +++ b/lib/libc/stdlib/Makefile.inc @@ -46,5 +46,5 @@ MLINKS+=strtod.3 strtof.3 strtod.3 strtold.3 MLINKS+=strtol.3 strtoll.3 strtol.3 strtoq.3 strtol.3 strtoimax.3 MLINKS+=strtoul.3 strtoull.3 strtoul.3 strtouq.3 strtoul.3 strtoumax.3 MLINKS+=malloc.3 calloc.3 malloc.3 free.3 malloc.3 malloc.conf.5 \ - malloc.3 realloc.3 malloc.3 reallocf.3 + malloc.3 realloc.3 malloc.3 reallocf.3 malloc.3 malloc_usable_size.3 MLINKS+=tsearch.3 tdelete.3 tsearch.3 tfind.3 tsearch.3 twalk.3 diff --git a/lib/libc/stdlib/Symbol.map b/lib/libc/stdlib/Symbol.map index 2459fe2..ff11d7a 100644 --- a/lib/libc/stdlib/Symbol.map +++ b/lib/libc/stdlib/Symbol.map @@ -53,6 +53,7 @@ FBSD_1.0 { calloc; realloc; free; + malloc_usable_size; mergesort; putenv; qsort_r; 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 . diff --git a/lib/libc/stdlib/malloc.c b/lib/libc/stdlib/malloc.c index 91357a0..359c98a 100644 --- a/lib/libc/stdlib/malloc.c +++ b/lib/libc/stdlib/malloc.c @@ -3489,6 +3489,26 @@ free(void *ptr) */ /******************************************************************************/ /* + * Begin non-standard functions. + */ + +size_t +malloc_usable_size(const void *ptr) +{ + + assert(ptr != NULL); + + if (ptr == &nil) + return (0); + else + return (isalloc(ptr)); +} + +/* + * End non-standard functions. + */ +/******************************************************************************/ +/* * Begin library-private functions, used by threading libraries for protection * of malloc during fork(). These functions are only called if the program is * running in threaded mode, so there is no need to check whether the program |
