mprotect(2)               SYSTEM CALLS                mprotect(2)



NAME
     mprotect - set protection of memory mapping

SYNOPSIS
     #include <sys/types.h>
     #include <sys/mman.h>
     int mprotect(caddrt addr, sizet len, int prot);

DESCRIPTION
     The function mprotect changes the access protections on  the
     mappings  specified  by  the  range [addr, addr + len) to be
     that specified by prot.  Legitimate values for prot are  the
     same  as  those  permitted  for  mmap  and  are  defined  in
     <sys/mman.h> as:
          PROTREAD                /* page can be read */
          PROTWRITE               /* page can be written */
          PROTEXEC                /* page can be executed */
          PROTNONE                /* page can not be accessed */

RETURN VALUE
     Upon successful completion, the function mprotect returns  a
     value  of  0;  otherwise,  it returns a value of -1 and sets
     errno to indicate an error.

ERRORS
     Under the following conditions, the function mprotect  fails
     and sets errno to:

     EACCES if prot specifies  a  protection  that  violates  the
            access  permission  the process has to the underlying
            memory object.

     EAGAIN if prot specifies PROTWRITE over a MAPPRIVATE  map-
            ping  and  there are insufficient memory resources to
            reserve for locking the private page.

     EINVAL if addr is  not  a  multiple  of  the  page  size  as
            returned by sysconf.

     EINVAL The argument len has a value less than or equal to 0.

     ENOMEM if 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.  When
            mprotect  fails  for  reasons  other than EINVAL, the
            protections on some of the pages in the range  [addr,
            addr  +  len)  may  have  been changed.  If the error
            occurs on some page at addr2, then the protections of
            all  whole pages in the range [addr, addr2] will have
            been modified.





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mprotect(2)               SYSTEM CALLS                mprotect(2)



SEE ALSO
     memcntl(2), mmap(2), plock(2), mlock(3C), mlockall(3C),
     sysconf(3C).




















































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