Java Native Access Platform 5.14.0 · com.sun.jna.platform.unix.LibCUtil

Modifier and Type	Field and Description
private static Function	ftruncate
private static boolean	ftruncate64
private static final NativeLibrary	LIBC
private static Function	mmap
private static boolean	mmap64

Access	Constructor and Description
private	LibCUtil()

Method Summary

Modifier and Type	Method and Description
public static int	Returns: On success, zero is returned. On error, -1 is returned, and `errno` is set appropriately. ftruncate(int a file descriptor fd, long the number of bytes to truncate or extend the file to length) Causes the regular file referenced by `fd` to be truncated to a size of precisely `length` bytes.
public static Pointer	Returns: On success, returns a pointer to the mapped area. On error, the value `MAP_FAILED` (that is, (void *) -1) is returned, and `errno` is set to indicate the cause of the error. mmap(Pointer The starting address for the new mapping. If `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 `addr` is 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. addr, long Specifies the length of the mapping (which must be greater than 0). length, int describes the desired memory protection of the mapping (and must not conflict with the open mode of the file). It is either `PROT_NONE` or the bitwise OR of one or more of `PROT_READ`, `PROT_WRITE`, or `PROT_EXEC`. prot, int 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_SHARED`, `MAP_SHARED_VALIDATE`, or `MAP_PRIVATE`. In addition, 0 or more additional flags can be ORed in `flags`. flags, int 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. fd, long The contents of a file mapping (as opposed to an anonymous mapping), are initialized using `length` bytes starting at offset `offset` in the file (or other object) referred to by the file descriptor, `fd`. `offset` must be a multiple of the page size as returned by `sysconf(_SC_PAGE_SIZE)`. offset) Creates a new mapping in the virtual address space of the calling process.
public static void	require32Bit(long The value to test val, String The name of the value, to be inserted in the exception message if not 32-bit value) Test that a value is 32-bit, throwing a custom exception otherwise

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

ftruncate	back to summary
private static Function ftruncate

ftruncate64	back to summary
private static boolean ftruncate64

LIBC	back to summary
private static final NativeLibrary LIBC

mmap	back to summary
private static Function mmap

mmap64	back to summary
private static boolean mmap64

LibCUtil	back to summary
private LibCUtil()

Method Detail

ftruncate back to summary

ftruncate	back to summary
public static int ftruncate(int fd, long length) Causes the regular file referenced by `fd` to be truncated to a size of precisely `length` bytes. 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 Parameters fd:int a file descriptor length:long the number of bytes to truncate or extend the file to Returns:int On success, zero is returned. On error, -1 is returned, and `errno` is set appropriately.

public static int ftruncate(int fd, long length)

Causes the regular file referenced by fd to be truncated to a size of precisely length bytes.

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

Parameters

fd:int: a file descriptor
length:long: the number of bytes to truncate or extend the file to

Returns:int

On success, zero is returned. On error, -1 is returned, and errno is set appropriately.

mmap back to summary

mmap	back to summary
public static Pointer mmap(Pointer addr, long length, int prot, int flags, int fd, long offset) Creates a new mapping in the virtual address space of the calling process. Parameters addr:Pointer The starting address for the new mapping. If `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 `addr` is 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:long Specifies the length of the mapping (which must be greater than 0). prot:int describes the desired memory protection of the mapping (and must not conflict with the open mode of the file). It is either `PROT_NONE` or the bitwise OR of one or more of `PROT_READ`, `PROT_WRITE`, or `PROT_EXEC`. flags:int 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_SHARED`, `MAP_SHARED_VALIDATE`, or `MAP_PRIVATE`. In addition, 0 or more additional flags can be ORed in `flags`. fd:int 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:long The contents of a file mapping (as opposed to an anonymous mapping), are initialized using `length` bytes starting at offset `offset` in the file (or other object) referred to by the file descriptor, `fd`. `offset` must be a multiple of the page size as returned by `sysconf(_SC_PAGE_SIZE)`. Returns:Pointer On success, returns a pointer to the mapped area. On error, the value `MAP_FAILED` (that is, (void *) -1) is returned, and `errno` is set to indicate the cause of the error.

public static Pointer mmap(Pointer addr, long length, int prot, int flags, int fd, long offset)

Creates a new mapping in the virtual address space of the calling process.

Parameters

addr:Pointer

The starting address for the new mapping.

If 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 addr is 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:long

Specifies the length of the mapping (which must be greater than 0).

prot:int

describes the desired memory protection of the mapping (and must not conflict with the open mode of the file). It is either PROT_NONE or the bitwise OR of one or more of PROT_READ, PROT_WRITE, or PROT_EXEC.

flags:int

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_SHARED, MAP_SHARED_VALIDATE, or MAP_PRIVATE. In addition, 0 or more additional flags can be ORed in flags.

fd:int

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:long

The contents of a file mapping (as opposed to an anonymous mapping), are initialized using length bytes starting at offset offset in the file (or other object) referred to by the file descriptor, fd. offset must be a multiple of the page size as returned by sysconf(_SC_PAGE_SIZE).

Returns:Pointer

On success, returns a pointer to the mapped area. On error, the value MAP_FAILED (that is, (void *) -1) is returned, and errno is set to indicate the cause of the error.

require32Bit back to summary

require32Bit	back to summary
public static void require32Bit(long val, String value) Test that a value is 32-bit, throwing a custom exception otherwise Parameters val:long The value to test value:String The name of the value, to be inserted in the exception message if not 32-bit Exceptions IllegalArgumentException: if `val` is not 32-bit

public static void require32Bit(long val, String value)

Test that a value is 32-bit, throwing a custom exception otherwise

Parameters

val:long: The value to test
value:String: The name of the value, to be inserted in the exception message if not 32-bit

Exceptions

IllegalArgumentException:: if val is not 32-bit

public Class LibCUtil

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