mincore(2)

NAME

     mincore - determine residency of memory pages

SYNOPSIS

     #include <sys/types.h>

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

DESCRIPTION

     The mincore()  function  determines  the  residency  of  the
     memory pages in the address space covered by mappings in the
     range [addr, addr +  len].  The  status  is  returned  as  a
     character-per-page in the character array referenced by *vec
     (which the system assumes to be large  enough  to  encompass
     all  the  pages in the address range). The least significant
     bit of each character is set  to  1  to  indicate  that  the
     referenced  page  is in primary memory, and to 0 to indicate
     that it is not. The settings of other bits in each character
     are  undefined  and  may contain other information in future
     implementations.

     Because the status of a page can  change  between  the  time
     mincore()  checks  and  returns  the  information,  returned
     information  might  be  outdated.  Only  locked  pages   are
     guaranteed to remain in memory; see mlock(3C).

RETURN VALUES

     Upon successful completion, mincore() returns 0.  Otherwise,
     -1 is returned and errno is set to indicate the error.

ERRORS

     The mincore() function will fail if:

     EFAULT
           The vec argument points to an illegal address.

     EINVAL
           The addr argument is not a multiple of the  page  size
           as returned by sysconf(3C), or the  len argument has a
           value less than or equal to 0.

     ENOMEM
           Addresses in the range [addr, addr + len] are  invalid
           for  the  address space of a process or specify one or
           more pages which are not mapped.

SEE ALSO

     mmap(2), mlock(3C), sysconf(3C)