// sigslot.h: Signal/Slot classes // // Written by Sarah Thompson (sarah@telergy.com) 2002. // // License: Public domain. You are free to use this code however you like, with // the proviso that the author takes on no responsibility or liability for any // use. // // QUICK DOCUMENTATION // // (see also the full documentation at http://sigslot.sourceforge.net/) // // #define switches // SIGSLOT_PURE_ISO: // Define this to force ISO C++ compliance. This also disables all of // the thread safety support on platforms where it is available. // // SIGSLOT_USE_POSIX_THREADS: // Force use of Posix threads when using a C++ compiler other than gcc // on a platform that supports Posix threads. (When using gcc, this is // the default - use SIGSLOT_PURE_ISO to disable this if necessary) // // SIGSLOT_DEFAULT_MT_POLICY: // Where thread support is enabled, this defaults to // multi_threaded_global. Otherwise, the default is single_threaded. // #define this yourself to override the default. In pure ISO mode, // anything other than single_threaded will cause a compiler error. // // PLATFORM NOTES // // Win32: // On Win32, the WEBRTC_WIN symbol must be #defined. Most mainstream // compilers do this by default, but you may need to define it yourself // if your build environment is less standard. This causes the Win32 // thread support to be compiled in and used automatically. // // Unix/Linux/BSD, etc.: // If you're using gcc, it is assumed that you have Posix threads // available, so they are used automatically. You can override this (as // under Windows) with the SIGSLOT_PURE_ISO switch. If you're using // something other than gcc but still want to use Posix threads, you // need to #define SIGSLOT_USE_POSIX_THREADS. // // ISO C++: // If none of the supported platforms are detected, or if // SIGSLOT_PURE_ISO is defined, all multithreading support is turned // off, along with any code that might cause a pure ISO C++ environment // to complain. Before you ask, gcc -ansi -pedantic won't compile this // library, but gcc -ansi is fine. Pedantic mode seems to throw a lot of // errors that aren't really there. If you feel like investigating this, // please contact the author. // // // THREADING MODES // // single_threaded: // Your program is assumed to be single threaded from the point of view // of signal/slot usage (i.e. all objects using signals and slots are // created and destroyed from a single thread). Behaviour if objects are // destroyed concurrently is undefined (i.e. you'll get the occasional // segmentation fault/memory exception). // // multi_threaded_global: // Your program is assumed to be multi threaded. Objects using signals // and slots can be safely created and destroyed from any thread, even // when connections exist. In multi_threaded_global mode, this is // achieved by a single global mutex (actually a critical section on // Windows because they are faster). This option uses less OS resources, // but results in more opportunities for contention, possibly resulting // in more context switches than are strictly necessary. // // multi_threaded_local: // Behaviour in this mode is essentially the same as // multi_threaded_global, except that each signal, and each object that // inherits has_slots, all have their own mutex/critical section. In // practice, this means that mutex collisions (and hence context // switches) only happen if they are absolutely essential. However, on // some platforms, creating a lot of mutexes can slow down the whole OS, // so use this option with care. // // USING THE LIBRARY // // See the full documentation at http://sigslot.sourceforge.net/ // // Libjingle specific: // // This file has been modified such that has_slots and signalx do not have to be // using the same threading requirements. E.g. it is possible to connect a // has_slots and signal0 or // has_slots and signal0. // If has_slots is single threaded the user must ensure that it is not trying // to connect or disconnect to signalx concurrently or data race may occur. // If signalx is single threaded the user must ensure that disconnect, connect // or signal is not happening concurrently or data race may occur. #ifndef WEBRTC_BASE_SIGSLOT_H_ #define WEBRTC_BASE_SIGSLOT_H_ // This header is deprecated and is just left here temporarily during // refactoring. See https://bugs.webrtc.org/7634 for more details. #include "webrtc/rtc_base/sigslot.h" #endif // WEBRTC_BASE_SIGSLOT_H_