MPROTECT(2)

NAME
mprotect - control the protection of pages

LIBRARY
libc

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

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.