libshevek
dl.hh
1 /* dl.hh - load dynamic libraries
2  * Copyright 2005 Bas Wijnen <wijnen@debian.org>
3  *
4  * This program is free software: you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation, either version 3 of the License, or
7  * (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program. If not, see <http://www.gnu.org/licenses/>.
16  */
17 
18 #ifndef SHEVEK_DL_HH
19 #define SHEVEK_DL_HH
20 
21 #include <string>
22 #include "dlfcn.h"
23 #include "refbase.hh"
24 #include "error.hh"
25 
26 namespace shevek
27 {
29 
31  class dl : public refbase
32  {
33  void *m_handle;
34  public:
36  static Glib::RefPtr <dl> create () { return Glib::RefPtr <dl> (new dl ()); }
38  ~dl ();
40  void open (std::string const &file = std::string ());
42 
44  void close ();
46 
48  template <typename T> T &get (std::string const &name);
49  protected:
50  dl ();
51  };
52 
53  template <typename T> T &dl::get (std::string const &name)
54  {
55  if (!m_handle)
56  shevek_error ("unable to get symbol: no valid handle");
57  union
58  {
59  void *input;
60  T *output;
61  } hack;
62  hack.input = dlsym (m_handle, name.c_str ());
63  if (!hack.input)
64  shevek_error (ostring ("unable to get symbol: %s", dlerror ()));
65  return *hack.output;
66  }
67 }
68 
69 #endif
shevek::ostring is a C++ version of printf.
Definition: iostring.hh:322
Load symbols from dynamic libraries.
Definition: dl.hh:31
Use normal files with the fd class.
Definition: file.hh:26
Base class for classes which want reference counting through Glib::RefPtr.
Definition: refbase.hh:27
void open(std::string const &file=std::string())
Open a shared library.
void close()
Close the library, freeing the resources.
Definition: args.hh:52
T & get(std::string const &name)
Get a symbol from the library.
Definition: dl.hh:53
~dl()
Close object and free structures.
static Glib::RefPtr< dl > create()
Create a new dl object.
Definition: dl.hh:36