NAME

       mprotect — control the protection of pages

LIBRARY

       Standard C Library (libc, -lc)

SYNOPSIS

       #include <sys/mman.h>

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

DESCRIPTION

       The  mprotect() system call changes the specified pages to have protection prot.  Not all implementations
       will guarantee protection on a page basis; the granularity of protection changes may be as  large  as  an
       entire  region.  A region is the virtual address space defined by the start and end addresses of a struct
       vm_map_entry.

       Currently these protection bits are known, which can be combined, OR'd together:

       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.

RETURN VALUES

       The mprotect() function returns the value 0 if successful; otherwise the value -1  is  returned  and  the
       global variable errno is set to indicate the error.

ERRORS

       The mprotect() system call will fail if:

       [EINVAL]           The virtual address range specified by the addr and len arguments is not valid.

       [EACCES]           The calling process was not allowed to change the protection to the value specified by
                          the prot argument.

SEE ALSO

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

HISTORY

       The mprotect() system call first appeared in 4.4BSD.

Debian                                            June 9, 1993                                       MPROTECT(2)