#include <sys/mman.h> int
mprotect (const void *addr size_t len int prot);
changes the specified pages to have protection
Fa 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
Vt struct vm_map_entry .
Currently these protection bits are known,
which can be combined, OR'd together:
No permissions at all.
The pages can be read.
The pages can be written.
The pages can be executed.
Rv -std mprotect
system call will fail if:
Bq Er EINVAL
The virtual address range specified by the
arguments is not valid.
Bq Er EACCES
The calling process was not allowed to change
the protection to the value specified by