oshi.jna.platform.unix

Interface CLibrary

All Superinterfaces:

com.sun.jna.Library

All Known Subinterfaces:

Libc, Libc, SystemB

public interface CLibrary
extends com.sun.jna.Library

C library with code common to all *nix-based operating systems. This class should be considered non-API as it may be removed if/when its code is incorporated into the JNA project.

Author:

widdis[at]gmail[dot]com

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	CLibrary.Addrinfo
static class	CLibrary.Sockaddr
static class	CLibrary.Timeval Return type for BSD sysctl kern.boottime

Nested classes/interfaces inherited from interface com.sun.jna.Library

com.sun.jna.Library.Handler

Field Summary

Fields

Modifier and Type	Field and Description
static int	AI_CANONNAME

Fields inherited from interface com.sun.jna.Library

OPTION_ALLOW_OBJECTS, OPTION_CALLING_CONVENTION, OPTION_CLASSLOADER, OPTION_FUNCTION_MAPPER, OPTION_INVOCATION_MAPPER, OPTION_OPEN_FLAGS, OPTION_STRING_ENCODING, OPTION_STRUCTURE_ALIGNMENT, OPTION_TYPE_MAPPER

Method Summary

Modifier and Type	Method and Description
void	freeaddrinfo(com.sun.jna.Pointer res) Frees the memory that was allocated for the dynamically allocated linked list res.
String	gai_strerror(int e) Translates getaddrinfo error codes to a human readable string, suitable for error reporting.
int	getaddrinfo(String node, String service, CLibrary.Addrinfo hints, com.sun.jna.ptr.PointerByReference res) Given node and service, which identify an Internet host and a service, getaddrinfo() returns one or more addrinfo structures, each of which contains an Internet address that can be specified in a call to bind(2) or connect(2).
int	getloadavg(double[] loadavg, int nelem) The getloadavg() function returns the number of processes in the system run queue averaged over various periods of time.
int	getpagesize() Returns the number of bytes in a memory page, where "page" is a fixed-length block, the unit for memory allocation and file mapping performed by mmap(2).
int	getpid() Returns the process ID of the calling process.
int	readlink(String path, com.sun.jna.Pointer buf, int bufsize) Places the contents of the symbolic link path in the buffer buf, which has size bufsiz.
int	sysctl(int[] name, int namelen, com.sun.jna.Pointer oldp, com.sun.jna.ptr.IntByReference oldlenp, com.sun.jna.Pointer newp, int newlen) The sysctl() function retrieves system information and allows processes with appropriate privileges to set system information.
int	sysctlbyname(String name, com.sun.jna.Pointer oldp, com.sun.jna.ptr.IntByReference oldlenp, com.sun.jna.Pointer newp, int newlen) The sysctlbyname() function accepts an ASCII representation of the name and internally looks up the integer name vector.
int	sysctlnametomib(String name, com.sun.jna.Pointer mibp, com.sun.jna.ptr.IntByReference size) The sysctlnametomib() function accepts an ASCII representation of the name, looks up the integer name vector, and returns the numeric representation in the mib array pointed to by mibp.

Field Detail

AI_CANONNAME

static final int AI_CANONNAME

See Also:

Constant Field Values

Method Detail

sysctl

int sysctl(int[] name,
           int namelen,
           com.sun.jna.Pointer oldp,
           com.sun.jna.ptr.IntByReference oldlenp,
           com.sun.jna.Pointer newp,
           int newlen)

The sysctl() function retrieves system information and allows processes with appropriate privileges to set system information. The information available from sysctl() consists of integers, strings, and tables. The state is described using a "Management Information Base" (MIB) style name, listed in name, which is a namelen length array of integers. The information is copied into the buffer specified by oldp. The size of the buffer is given by the location specified by oldlenp before the call, and that location gives the amount of data copied after a successful call and after a call that returns with the error code ENOMEM. If the amount of data available is greater than the size of the buffer supplied, the call supplies as much data as fits in the buffer provided and returns with the error code ENOMEM. If the old value is not desired, oldp and oldlenp should be set to NULL. The size of the available data can be determined by calling sysctl() with the NULL argument for oldp. The size of the available data will be returned in the location pointed to by oldlenp. For some operations, the amount of space may change often. For these operations, the system attempts to round up so that the returned size is large enough for a call to return the data shortly thereafter. To set a new value, newp is set to point to a buffer of length newlen from which the requested value is to be taken. If a new value is not to be set, newp should be set to NULL and newlen set to 0.

Parameters:

name - MIB array of integers

namelen - length of the MIB array

oldp - Information retrieved

oldlenp - Size of information retrieved

newp - Information to be written

newlen - Size of information to be written

Returns:

0 on success; sets errno on failure

sysctlbyname

int sysctlbyname(String name,
                 com.sun.jna.Pointer oldp,
                 com.sun.jna.ptr.IntByReference oldlenp,
                 com.sun.jna.Pointer newp,
                 int newlen)

The sysctlbyname() function accepts an ASCII representation of the name and internally looks up the integer name vector. Apart from that, it behaves the same as the standard sysctl() function.

Parameters:

name - ASCII representation of the MIB name

oldp - Information retrieved

oldlenp - Size of information retrieved

newp - Information to be written

newlen - Size of information to be written

Returns:

0 on success; sets errno on failure

sysctlnametomib

int sysctlnametomib(String name,
                    com.sun.jna.Pointer mibp,
                    com.sun.jna.ptr.IntByReference size)

The sysctlnametomib() function accepts an ASCII representation of the name, looks up the integer name vector, and returns the numeric representation in the mib array pointed to by mibp. The number of elements in the mib array is given by the location specified by sizep before the call, and that location gives the number of entries copied after a successful call. The resulting mib and size may be used in subsequent sysctl() calls to get the data associated with the requested ASCII name. This interface is intended for use by applications that want to repeatedly request the same variable (the sysctl() function runs in about a third the time as the same request made via the sysctlbyname() function). The number of elements in the mib array can be determined by calling sysctlnametomib() with the NULL argument for mibp. The sysctlnametomib() function is also useful for fetching mib prefixes. If size on input is greater than the number of elements written, the array still contains the additional elements which may be written programmatically.

Parameters:

name - ASCII representation of the name

mibp - Integer array containing the corresponding name vector.

size - On input, number of elements in the returned array; on output, the number of entries copied.

Returns:

0 on success; sets errno on failure

getloadavg

int getloadavg(double[] loadavg,
               int nelem)

The getloadavg() function returns the number of processes in the system run queue averaged over various periods of time. Up to nelem samples are retrieved and assigned to successive elements of loadavg[]. The system imposes a maximum of 3 samples, representing averages over the last 1, 5, and 15 minutes, respectively.

Parameters:

loadavg - An array of doubles which will be filled with the results

nelem - Number of samples to return

Returns:

If the load average was unobtainable, -1 is returned; otherwise, the number of samples actually retrieved is returned.

See Also:

getloadavg(3)

getpid

int getpid()

Returns the process ID of the calling process. The ID is guaranteed to be unique and is useful for constructing temporary file names.

Returns:

the process ID of the calling process.

getaddrinfo

int getaddrinfo(String node,
                String service,
                CLibrary.Addrinfo hints,
                com.sun.jna.ptr.PointerByReference res)

Given node and service, which identify an Internet host and a service, getaddrinfo() returns one or more addrinfo structures, each of which contains an Internet address that can be specified in a call to bind(2) or connect(2).

Parameters:

node - a numerical network address or a network hostname, whose network addresses are looked up and resolved.

service - sets the port in each returned address structure.

hints - specifies criteria for selecting the socket address structures returned in the list pointed to by res.

res - returned address structure

Returns:

0 on success; sets errno on failure

freeaddrinfo

void freeaddrinfo(com.sun.jna.Pointer res)

Frees the memory that was allocated for the dynamically allocated linked list res.

Parameters:

res - Pointer to linked list returned by getaddrinfo

gai_strerror

String gai_strerror(int e)

Translates getaddrinfo error codes to a human readable string, suitable for error reporting.

Parameters:

e - Error code from getaddrinfo

Returns:

A human-readable version of the error code

readlink

int readlink(String path,
             com.sun.jna.Pointer buf,
             int bufsize)

Places the contents of the symbolic link path in the buffer buf, which has size bufsiz.

Parameters:

path - A symbolic link

buf - Holds actual path to location pointed to by symlink

bufsize - size of data in buffer

Returns:

readlink() places the contents of the symbolic link path in the buffer buf, which has size bufsiz. readlink() does not append a null byte to buf. It will truncate the contents (to a length of bufsiz characters), in case the buffer is too small to hold all of the contents.

getpagesize

int getpagesize()

Returns the number of bytes in a memory page, where "page" is a fixed-length block, the unit for memory allocation and file mapping performed by mmap(2).

Returns:

the memory page size