The Fiddle::Handle is the manner to access the dynamic library

Example

Setup

libc_so = "/lib64/libc.so.6"
=> "/lib64/libc.so.6"
@handle = Fiddle::Handle.new(libc_so)
=> #<Fiddle::Handle:0x00000000d69ef8>

Setup, with flags

libc_so = "/lib64/libc.so.6"
=> "/lib64/libc.so.6"
@handle = Fiddle::Handle.new(libc_so, Fiddle::RTLD_LAZY | Fiddle::RTLD_GLOBAL)
=> #<Fiddle::Handle:0x00000000d69ef8>

See RTLD_LAZY and RTLD_GLOBAL

Addresses to symbols

strcpy_addr = @handle['strcpy']
=> 140062278451968

or

strcpy_addr = @handle.sym('strcpy')
=> 140062278451968
Constants

NEXT

A predefined pseudo-handle of RTLD_NEXT

Which will find the next occurrence of a function in the search order after the current library.

DEFAULT

A predefined pseudo-handle of RTLD_DEFAULT

Which will find the first occurrence of the desired symbol using the default library search order

RTLD_GLOBAL

rtld Fiddle::Handle flag.

The symbols defined by this library will be made available for symbol resolution of subsequently loaded libraries.

RTLD_LAZY

rtld Fiddle::Handle flag.

Perform lazy binding. Only resolve symbols as the code that references them is executed. If the symbol is never referenced, then it is never resolved. (Lazy binding is only performed for function references; references to variables are always immediately bound when the library is loaded.)

RTLD_NOW

rtld Fiddle::Handle flag.

If this value is specified or the environment variable LD_BIND_NOW is set to a nonempty string, all undefined symbols in the library are resolved before Fiddle.dlopen returns. If this cannot be done an error is returned.

Class Methods

Get the address as an Integer for the function named name. The function is searched via dlsym on RTLD_NEXT.

See man(3) dlsym() for more info.

Create a new handler that opens library with flags.

If no library is specified or nil is given, DEFAULT is used, which is the equivalent to RTLD_DEFAULT. See man 3 dlopen for more.

lib = Fiddle::Handle.new

The default is dependent on OS, and provide a handle for all libraries already loaded. For example, in most cases you can use this to access libc functions, or ruby functions like rb_str_new.

Get the address as an Integer for the function named name.

Instance Methods
An alias for sym

Close this handle.

Calling close more than once will raise a Fiddle::DLError exception.

Returns true if dlclose() will be called when this handle is garbage collected.

See man(3) dlclose() for more info.

Disable a call to dlclose() when this handle is garbage collected.

Enable a call to dlclose() when this handle is garbage collected.

Returns the file name of this handle.

Get the address as an Integer for the function named name.

Returns the memory address for this handle.

Returns the Fiddle::Pointer of this handle.