valloc.3

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)valloc.3	8.1	9/11/90
.TH valloc 3
.SH Name
valloc \- aligned memory allocator
.SH Syntax
.nf
.B #include <stdlib.h>
.PP
.B void *valloc(\fIsize\fP) 
.B size_t \fIsize\fP; 
.fi
.SH Description
.NXR "valloc subroutine"
.NXR "memory" "allocating"
The
.PN valloc
subroutine allocates
.I size
bytes aligned on a page boundary.
It is implemented by calling 
.MS malloc 3 
with a slightly larger request, saving the true beginning of the block
allocated, and returning a properly aligned pointer.
.SH Diagnostics
The
.PN valloc
subroutine
returns a null pointer (0) if there is no available memory
or if the arena has been detectably
corrupted by storing outside the bounds
of a block.
The
.PN valloc
subroutine will fail and no additional memory will be allocated if
one of the following is true:
.TP 12
[ENOMEM]
The limit, as set by
.MS setrlimit 2 ,
is exceeded.
.TP
[ENOMEM]
The maximum possible size of a data segment (compiled into the
system) is exceeded.
.TP
[ENOMEM]
Insufficient space exists in the swap area to support the expansion.