Class: FFI::DynamicLibrary

Inherits:
Object
  • Object
show all
Defined in:
lib/ffi/dynamic_library.rb,
ext/ffi_c/DynamicLibrary.c

Defined Under Namespace

Classes: Symbol

Constant Summary collapse

SEARCH_PATH = 
[]
SEARCH_PATH_MESSAGE = 
"Searched in <system library path>#{ SEARCH_PATH.map{|a| ', ' + a}.join }".freeze

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(libname, libflags) ⇒ FFI::DynamicLibrary

A new DynamicLibrary instance.

Parameters:

  • libname (String) —

    name of library to open

  • libflags (Integer) —

    flags for library to open

Raises:

  • (LoadError) —

    if libname cannot be opened



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# File 'ext/ffi_c/DynamicLibrary.c', line 136

static VALUE
library_initialize(VALUE self, VALUE libname, VALUE libflags)
{
    Library* library;
    int flags;

    Check_Type(libflags, T_FIXNUM);

    TypedData_Get_Struct(self, Library, &rbffi_library_data_type, library);
    flags = libflags != Qnil ? NUM2UINT(libflags) : 0;

    library->handle = dl_open(libname != Qnil ? StringValueCStr(libname) : NULL, flags);
    if (library->handle == NULL) {
        char errmsg[1024];
        dl_error(errmsg, sizeof(errmsg));
        rb_raise(rb_eLoadError, "Could not open library '%s': %s",
                libname != Qnil ? StringValueCStr(libname) : "[current process]",
                errmsg);
    }
#ifdef __CYGWIN__
    // On Cygwin 1.7.17 "dlsym(dlopen(0,0), 'getpid')" fails. (dlerror: "No such process")
    // As a workaround we can use "dlsym(RTLD_DEFAULT, 'getpid')" instead.
    // Since 0 == RTLD_DEFAULT we won't call dl_close later.
    if (libname == Qnil) {
        dl_close(library->handle);
        library->handle = RTLD_DEFAULT;
    }
#endif
    rb_iv_set(self, "@name", libname != Qnil ? rb_str_new_frozen(libname) : rb_str_new2("[current process]"));

    rb_obj_freeze(self);
    return self;
}

Instance Attribute Details

#name ⇒ Object (readonly)

Class Method Details

.last_error ⇒ String

Returns library’s last error string.

Returns:

  • (String) —

    library’s last error string



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# File 'ext/ffi_c/DynamicLibrary.c', line 187

static VALUE
library_dlerror(VALUE self)
{
    char errmsg[1024];
    dl_error(errmsg, sizeof(errmsg));
    return rb_str_new2(errmsg);
}

.open(libname, libflags) ⇒ FFI::DynamicLibrary

Open a library.

Parameters:

  • libname (String) —

    name of library to open

  • libflags (Integer) —

    flags for library to open

Returns:

Raises:

  • (LoadError) —

    if libname cannot be opened



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# File 'ext/ffi_c/DynamicLibrary.c', line 122

static VALUE
library_open(VALUE klass, VALUE libname, VALUE libflags)
{
    return library_initialize(library_allocate(klass), libname, libflags);
}

Instance Method Details

#find_function(name) ⇒ FFI::DynamicLibrary::Symbol

Returns library function symbol.

Parameters:

  • name (String) —

    library function’s name

Returns:



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# File 'ext/ffi_c/DynamicLibrary.c', line 170

static VALUE
library_dlsym(VALUE self, VALUE name)
{
    Library* library;
    void* address = NULL;
    Check_Type(name, T_STRING);

    TypedData_Get_Struct(self, Library, &rbffi_library_data_type, library);
    address = dl_sym(library->handle, StringValueCStr(name));

    return address != NULL ? symbol_new(self, address, name) : Qnil;
}

#find_symbol(name) ⇒ FFI::DynamicLibrary::Symbol

Returns library symbol.

Parameters:

  • name (String) —

    library symbol’s name

Returns:



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# File 'ext/ffi_c/DynamicLibrary.c', line 170

static VALUE
library_dlsym(VALUE self, VALUE name)
{
    Library* library;
    void* address = NULL;
    Check_Type(name, T_STRING);

    TypedData_Get_Struct(self, Library, &rbffi_library_data_type, library);
    address = dl_sym(library->handle, StringValueCStr(name));

    return address != NULL ? symbol_new(self, address, name) : Qnil;
}

#find_variable(name) ⇒ FFI::DynamicLibrary::Symbol

Returns library variable symbol.

Parameters:

  • name (String) —

    library variable’s name

Returns:



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# File 'ext/ffi_c/DynamicLibrary.c', line 170

static VALUE
library_dlsym(VALUE self, VALUE name)
{
    Library* library;
    void* address = NULL;
    Check_Type(name, T_STRING);

    TypedData_Get_Struct(self, Library, &rbffi_library_data_type, library);
    address = dl_sym(library->handle, StringValueCStr(name));

    return address != NULL ? symbol_new(self, address, name) : Qnil;
}

#last_error ⇒ String

Returns library’s last error string.

Returns:

  • (String) —

    library’s last error string



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# File 'ext/ffi_c/DynamicLibrary.c', line 187

static VALUE
library_dlerror(VALUE self)
{
    char errmsg[1024];
    dl_error(errmsg, sizeof(errmsg));
    return rb_str_new2(errmsg);
}