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MPROTECT(2)                 BSD System Calls Manual                MPROTECT(2)

     mprotect -- control the protection of pages

     #include <sys/mman.h>

     mprotect(void *addr, size_t len, int prot);

     The mprotect() system call changes the specified pages to have protection prot.  Not all implementa-tions implementations
     tions will guarantee protection on a page basis but Mac OS X's current implementation does.

     When a program violates the protections of a page, it gets a SIGBUS or SIGSEGV signal.

     Currently prot can be one or more of the following:

     PROT_NONE   No permissions at all.
     PROT_READ   The pages can be read.
     PROT_WRITE  The pages can be written.
     PROT_EXEC   The pages can be executed.

     Upon successful completion, a value of 0 is returned.  Otherwise, a value of -1 is returned and errno
     is set to indicate the error.

     mprotect() will fail if:

     [EACCES]           The requested protection conflicts with the access permissions of the process on the
                        specified address range.

     [EINVAL]           addr is not a multiple of the page size (i.e.  addr is not page-aligned).

     [ENOTSUP]          The combination of accesses requested in prot is not supported.

     #include <sys/types.h>
     #include <sys/mman.h>

     The include file <sys/types.h> is necessary.

     mprotect(caddr_t addr, size_t len, int prot);

     The type of addr has changed.

     madvise(2), mincore(2), msync(2), munmap(2), compat(5)

     The mprotect() function first appeared in 4.4BSD.

BSD                            October 16, 2008                            BSD

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