Class DynamicLinkLoader
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Field Summary
Modifier and TypeFieldDescriptionstatic final long
Special-handle values fordlsym(long, java.nio.ByteBuffer)
.static final int
Themode
argument todlopen(java.nio.ByteBuffer, int)
contains one of the following.static final int
Themode
argument todlopen(java.nio.ByteBuffer, int)
contains one of the following.static final int
Themode
argument todlopen(java.nio.ByteBuffer, int)
contains one of the following.static final long
Special-handle values fordlsym(long, java.nio.ByteBuffer)
.static final long
Special-handle values fordlsym(long, java.nio.ByteBuffer)
.static final int
Themode
argument todlopen(java.nio.ByteBuffer, int)
contains one of the following.static final long
Special-handle values fordlsym(long, java.nio.ByteBuffer)
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Method Summary
Modifier and TypeMethodDescriptionstatic int
dlclose
(long handle) Closes a dynamic library or bundle.static String
dlerror()
Provides diagnostic information corresponding to problems with calls todlopen(java.nio.ByteBuffer, int)
,dlsym(long, java.nio.ByteBuffer)
, anddlclose(long)
in the same thread.static long
dlopen
(CharSequence path, int mode) Loads and links a dynamic library or bundle.static long
dlopen
(ByteBuffer path, int mode) Loads and links a dynamic library or bundle.static long
dlsym
(long handle, CharSequence name) Returns the address of a symbol.static long
dlsym
(long handle, ByteBuffer name) Returns the address of a symbol.static int
ndlclose
(long handle) Unsafe version of:dlclose(long)
static long
ndlerror()
Unsafe version of:dlerror()
static long
ndlopen
(long path, int mode) Unsafe version of:dlopen(java.nio.ByteBuffer, int)
static long
ndlsym
(long handle, long name) Unsafe version of:dlsym(long, java.nio.ByteBuffer)
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Field Details
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RTLD_LAZY
public static final int RTLD_LAZYThemode
argument todlopen(java.nio.ByteBuffer, int)
contains one of the following.- See Also:
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RTLD_NOW
public static final int RTLD_NOWThemode
argument todlopen(java.nio.ByteBuffer, int)
contains one of the following.- See Also:
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RTLD_LOCAL
public static final int RTLD_LOCALThemode
argument todlopen(java.nio.ByteBuffer, int)
contains one of the following.- See Also:
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RTLD_GLOBAL
public static final int RTLD_GLOBALThemode
argument todlopen(java.nio.ByteBuffer, int)
contains one of the following.- See Also:
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RTLD_NEXT
public static final long RTLD_NEXTSpecial-handle values fordlsym(long, java.nio.ByteBuffer)
.- See Also:
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RTLD_DEFAULT
public static final long RTLD_DEFAULTSpecial-handle values fordlsym(long, java.nio.ByteBuffer)
.- See Also:
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RTLD_SELF
public static final long RTLD_SELFSpecial-handle values fordlsym(long, java.nio.ByteBuffer)
.- See Also:
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RTLD_MAIN_ONLY
public static final long RTLD_MAIN_ONLYSpecial-handle values fordlsym(long, java.nio.ByteBuffer)
.- See Also:
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Method Details
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ndlopen
public static long ndlopen(long path, int mode) Unsafe version of:dlopen(java.nio.ByteBuffer, int)
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dlopen
Loads and links a dynamic library or bundle.This function examines the Mach-O file specified by path. If the image is compatible with the current process and has not already been loaded into the process, the image is loaded and linked. If the image contains initializer functions, they are executed before this function returns.
Subsequent calls to
dlopen
to load the same image return the same handle, but the internal reference count for the handle is incremented. Therefore, alldlopen
calls must be balanced withdlclose(long)
calls.For efficiency, the
RTLD_LAZY
binding mode is preferred overRTLD_NOW
. However, usingRTLD_NOW
ensures that any undefined symbols are discovered during the call todlopen
.The dynamic loader looks in the paths specified by a set of environment variables, and in the process's current directory, when it searches for a library. These paths are called dynamic loader search paths. The environment variables are
LD_LIBRARY_PATH
,DYLD_LIBRARY_PATH
, andDYLD_FALLBACK_LIBRARY_PATH
. The default value ofDYLD_FALLBACK_LIBRARY_PATH
(used when this variable is not set), is$HOME/lib;/usr/local/lib;/usr/lib
.The order in which the search paths are searched depends on whether path is a filename (it does not contain a slash) or a pathname (it contains at least one slash).
When path is a filename, the dynamic loader searches for the library in the search paths in the following order:
- $LD_LIBRARY_PATH
- $DYLD_LIBRARY_PATH
- The process's working directory
- $DYLD_FALLBACK_LIBRARY_PATH
When path is a pathname, the dynamic loader searches for the library in the search paths in the following order:
- $DYLD_LIBRARY_PATH
- The given pathname
- $DYLD_FALLBACK_LIBRARY_PATH using the filename
- Parameters:
path
- path to the image to openmode
- specifies when the loaded image's external symbols are bound to their definitions in dependent libraries (lazy or at load time) and the visibility of the image's exported symbols (global or local). The value of this parameter is made up by ORing one binding behavior value with one visibility specification value.The following values specify the binding behavior:
RTLD_LAZY
(default): Each external symbol reference is bound the first time it's used.RTLD_NOW
: All external symbol references are bound immediately.
The following values specify external symbol visibility:
RTLD_GLOBAL
(default): The loaded image's exported symbols are available to any images that use a flat namespace or to calls to dlsym when using a special handle (seedlsym(long, java.nio.ByteBuffer)
for details).RTLD_LOCAL
: The loaded image's exported symbols are generally hidden. They are available only todlsym(long, java.nio.ByteBuffer)
invocations that use the handle returned by this function.
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dlopen
Loads and links a dynamic library or bundle.This function examines the Mach-O file specified by path. If the image is compatible with the current process and has not already been loaded into the process, the image is loaded and linked. If the image contains initializer functions, they are executed before this function returns.
Subsequent calls to
dlopen
to load the same image return the same handle, but the internal reference count for the handle is incremented. Therefore, alldlopen
calls must be balanced withdlclose(long)
calls.For efficiency, the
RTLD_LAZY
binding mode is preferred overRTLD_NOW
. However, usingRTLD_NOW
ensures that any undefined symbols are discovered during the call todlopen
.The dynamic loader looks in the paths specified by a set of environment variables, and in the process's current directory, when it searches for a library. These paths are called dynamic loader search paths. The environment variables are
LD_LIBRARY_PATH
,DYLD_LIBRARY_PATH
, andDYLD_FALLBACK_LIBRARY_PATH
. The default value ofDYLD_FALLBACK_LIBRARY_PATH
(used when this variable is not set), is$HOME/lib;/usr/local/lib;/usr/lib
.The order in which the search paths are searched depends on whether path is a filename (it does not contain a slash) or a pathname (it contains at least one slash).
When path is a filename, the dynamic loader searches for the library in the search paths in the following order:
- $LD_LIBRARY_PATH
- $DYLD_LIBRARY_PATH
- The process's working directory
- $DYLD_FALLBACK_LIBRARY_PATH
When path is a pathname, the dynamic loader searches for the library in the search paths in the following order:
- $DYLD_LIBRARY_PATH
- The given pathname
- $DYLD_FALLBACK_LIBRARY_PATH using the filename
- Parameters:
path
- path to the image to openmode
- specifies when the loaded image's external symbols are bound to their definitions in dependent libraries (lazy or at load time) and the visibility of the image's exported symbols (global or local). The value of this parameter is made up by ORing one binding behavior value with one visibility specification value.The following values specify the binding behavior:
RTLD_LAZY
(default): Each external symbol reference is bound the first time it's used.RTLD_NOW
: All external symbol references are bound immediately.
The following values specify external symbol visibility:
RTLD_GLOBAL
(default): The loaded image's exported symbols are available to any images that use a flat namespace or to calls to dlsym when using a special handle (seedlsym(long, java.nio.ByteBuffer)
for details).RTLD_LOCAL
: The loaded image's exported symbols are generally hidden. They are available only todlsym(long, java.nio.ByteBuffer)
invocations that use the handle returned by this function.
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ndlerror
public static long ndlerror()Unsafe version of:dlerror()
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dlerror
Provides diagnostic information corresponding to problems with calls todlopen(java.nio.ByteBuffer, int)
,dlsym(long, java.nio.ByteBuffer)
, anddlclose(long)
in the same thread.When there's a problem to report, this function returns a pointer to a null-terminated string describing the problem. Otherwise, this function returns
NULL
.Each call to
dlerror
resets its diagnostic buffer. If a program needs to keep a record of past error messages, it must store them itself. Subsequent calls todlerror
in the same thread with no calls todlopen(java.nio.ByteBuffer, int)
,dlsym(long, java.nio.ByteBuffer)
, ordlclose(long)
, returnNULL
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ndlsym
public static long ndlsym(long handle, long name) Unsafe version of:dlsym(long, java.nio.ByteBuffer)
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dlsym
Returns the address of a symbol.The value of handle specifies what images this function searches for to locate the symbol specified by the symbol parameter. The following table describes the possible values for the handle parameter:
Handle value Search scope dlopen
handleImage associated with the dlopen(java.nio.ByteBuffer, int)
handle.RTLD_DEFAULT
Every dependent library or RTLD_GLOBAL
–opened library in the current process, in the order they were loaded.RTLD_NEXT
Dependent libraries that were loaded after the one calling this function. Libraries opened with dlopen(java.nio.ByteBuffer, int)
are not searched.Unlike in the NS... functions, the symbol parameter doesn't require a leading underscore to be part of the symbol name.
- Parameters:
handle
- a handle obtained by a call todlopen(java.nio.ByteBuffer, int)
, or a special handle. If the handle was obtained by a call todlopen(java.nio.ByteBuffer, int)
, it must not have been closed with a call todlclose(long)
. These are the possible special-handle values:RTLD_DEFAULT
, andRTLD_NEXT
.name
- the null-terminated character string containing the C name of the symbol being sought
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dlsym
Returns the address of a symbol.The value of handle specifies what images this function searches for to locate the symbol specified by the symbol parameter. The following table describes the possible values for the handle parameter:
Handle value Search scope dlopen
handleImage associated with the dlopen(java.nio.ByteBuffer, int)
handle.RTLD_DEFAULT
Every dependent library or RTLD_GLOBAL
–opened library in the current process, in the order they were loaded.RTLD_NEXT
Dependent libraries that were loaded after the one calling this function. Libraries opened with dlopen(java.nio.ByteBuffer, int)
are not searched.Unlike in the NS... functions, the symbol parameter doesn't require a leading underscore to be part of the symbol name.
- Parameters:
handle
- a handle obtained by a call todlopen(java.nio.ByteBuffer, int)
, or a special handle. If the handle was obtained by a call todlopen(java.nio.ByteBuffer, int)
, it must not have been closed with a call todlclose(long)
. These are the possible special-handle values:RTLD_DEFAULT
, andRTLD_NEXT
.name
- the null-terminated character string containing the C name of the symbol being sought
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ndlclose
public static int ndlclose(long handle) Unsafe version of:dlclose(long)
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dlclose
public static int dlclose(long handle) Closes a dynamic library or bundle.This function decreases the reference count of the image referenced by handle. When the reference count for handle becomes 0, the termination routines in the image are called, and the image is removed from the address space of the current process. After that point, handle is rendered invalid.
- Parameters:
handle
- a handle obtained through a call todlopen(java.nio.ByteBuffer, int)
.
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