On Sat, 23 Nov 2002, David Schultz wrote: > Thus spake Bruce Evans <[EMAIL PROTECTED]>: > > ... C90 has a bogus requirement that > > the pointer for malloc(0) be "unique", whatever that means. C99 only > > requires that the objects pointed to by the results of malloc() be > > disjoint, and this is satisfied by FreeBSD's behaviour of returning the > > same magic pointer for each instance of malloc(0). > > In FreeBSD, malloc(0) returns a distinct pointer each time by > making a 16-byte allocation. I seem to recall that it may have > returned a single magic pointer at one time, so what you say might > have been correct some time ago.
Actually, it is correct now. malloc(0) returns the constant invalid pointer ZEROSIZEPTR (0x800 on i386's), but it returned a distinct pointer before the ZEROSIZEPTR stuff was added in rev.1.60 of libc/stdlib/malloc.c. (All this is without the malloc option V which causes malloc(0) to return a null pointer.) Bruce To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-current" in the body of the message
