MADVISE(2)                      Domain/OS BSD                       MADVISE(2)



NAME
     madvise, mincore - advise the system of a process' expected paging
     behavior

SYNOPSIS
     #include <sys/mman.h>

     madvise(addr, len, behav)
     caddr_t addr;
     int len, behav;

     mincore(addr, len, vec)
     caddr_t addr;
     int len;
     char *vec;

DESCRIPTION
     madvise advises the kernel what to expect regarding a process' paging
     behavior, where addr is starting address of the region for which advice
     is given, len is the length of the region, and behav describes expected
     behavior.  <sys/mman.h> defines the following behaviors:

     #define  MADV_NORMAL      0     /* no further special treatment */
     #define  MADV_RANDOM      1     /* expect random page references */
     #define  MADV_SEQUENTIAL  2     /* expect sequential references */
     #define  MADV_WILLNEED    3     /* will need these pages */
     #define  MADV_DONTNEED    4     /* don't need these pages */
     #define  MADV_SPACEAVAIL  5     /* insure that resources are reserved */

     mincore returns 1 in vec if the region starting at address addr with
     length len is core-resident.

NOTES
     Domain/OS BSD ignores the WILLNEED and DONTNEED behaviors.  mincore
     always returns 1 for all pages in the region.

     This implementation is based upon a proposal by McKusick and Karels, and
     upon other sources.  Its details may change in a future release.

SEE ALSO
     McKusick, M.K. and Karels, M.J.  A New Virtual Memory Implementation for
          Berkeley UNIX.  Berkeley, California:  Department of Electrical
          Engineering and Computer Science, University of California, 1986.
     mmap(2), mprotect(2), mset(2).

DIAGNOSTICS
     madvise and mincore return 0 if successful.  Otherwise, they return -1.

ERRORS
     madvise will fail if either of the following is true:

     [EINVAL]  An unknown behavior was specified.

     [ENOENT]  No region is mapped at the specified address.