public class LibCUtil extends java.lang.Object
off_tbecause it is dependent upon features selected at compile-time. This class provides helper methods that safely avoid these types by using 64-bit mappings when available.
|Modifier and Type||Method and Description|
Causes the regular file referenced by
Creates a new mapping in the virtual address space of the calling process.
Test that a value is 32-bit, throwing a custom exception otherwise
addr- The starting address for the new mapping.
addr is NULL, then the kernel chooses the
(page-aligned) address at which to create the mapping; this is the
most portable method of creating a new mapping. If
not NULL, then the kernel takes it as a hint about where to place
the mapping; on Linux, the kernel will pick a nearby page boundary
(but always above or equal to the value specified by
/proc/sys/vm/mmap_min_addr) and attempt to create the
mapping there. If another mapping already exists there, the kernel
picks a new address that may or may not depend on the hint. The
address of the new mapping is returned as the result of the call.
length- Specifies the length of the mapping (which must be greater than 0).
prot- describes the desired memory protection of the mapping (and must not conflict with the open mode of the file). It is either
PROT_NONEor the bitwise OR of one or more of
flags- determines whether updates to the mapping are visible to other processes mapping the same region, and whether updates are carried through to the underlying file. This behavior is determined by including exactly one of
MAP_PRIVATE. In addition, 0 or more additional flags can be ORed in
fd- The file descriptor for the object to be mapped. After the
mmap()call has returned, the file descriptor can be closed immediately without invalidating the mapping.
offset- The contents of a file mapping (as opposed to an anonymous mapping), are initialized using
lengthbytes starting at offset
offsetin the file (or other object) referred to by the file descriptor,
offsetmust be a multiple of the page size as returned by
MAP_FAILED(that is, (void *) -1) is returned, and
errnois set to indicate the cause of the error.
public static int ftruncate(int fd, long length)
fdto be truncated to a size of precisely
If the file previously was larger than this size, the extra data is lost. If the file previously was shorter, it is extended, and the extended part reads as null bytes ('\0').
The file must be open for writing
fd- a file descriptor
length- the number of bytes to truncate or extend the file to
errnois set appropriately.
public static void require32Bit(long val, java.lang.String value)
val- The value to test
value- The name of the value, to be inserted in the exception message if not 32-bit
valis not 32-bit