control the protection of pages
Standard C Library (libc, -lc)
() system call changes the
specified pages to have protection prot
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
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.
() function returns the
value 0 if successful; otherwise the value -1 is returned and
the global variable errno
is set to indicate
() system call will fail if:
- The virtual address range specified by the
len arguments is not valid.
- The calling process was not allowed to change the protection to the value
specified by the prot argument.
() system call first appeared in