Wrapper to mprotect system call. Not all
implementations will guarantee protection.
Usage
mprotect(x, i, prot)
Arguments
x
mmap object.
i
location and length of pages to protect.
prot
protection flag set by mmapFlags.
Must be one or more of:
PROT_NONE,
PROT_READ,
PROT_WRITE,
PROT_EXEC.
Value
0 upon success, otherwise -1.
Details
This functionality is very experimental, and likely to
be of limited use with R, as the result of a page access
that is protected is a SIG that isn't likely to
be caught by R. This may be of use for other programs
sharing resource with R.