The Linux Programming Interface: a linux and unix system Programming Handbook
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ALTERNATIVE I/O MODELS 1325 63.1 Overview ............................................................................................................... 1325 63.1.1 Level-Triggered and Edge-Triggered Notification..................................... 1329 63.1.2 Employing Nonblocking I/O with Alternative I/O Models ....................... 1330 63.2 I/O Multiplexing ..................................................................................................... 1330 63.2.1 The select() System Call........................................................................ 1331 63.2.2 The poll() System Call ......................................................................... 1337 63.2.3 When Is a File Descriptor Ready? ......................................................... 1341 63.2.4 Comparison of select() and poll() .......................................................... 1344 63.2.5 Problems with select() and poll() ............................................................ 1346 63.3 Signal-Driven I/O.................................................................................................... 1346 63.3.1 When Is “I/O Possible” Signaled? ........................................................ 1351 63.3.2 Refining the Use of Signal-Driven I/O.................................................... 1352 63.4 The epoll API........................................................................................................... 1355 63.4.1 Creating an epoll Instance: epoll_create() ............................................... 1356 63.4.2 Modifying the epoll Interest List: epoll_ctl() ............................................. 1356 63.4.3 Waiting for Events: epoll_wait() ............................................................ 1358 63.4.4 A Closer Look at epoll Semantics .......................................................... 1363 63.4.5 Performance of epoll Versus I/O Multiplexing......................................... 1365 63.4.6 Edge-Triggered Notification ................................................................. 1366 63.5 Waiting on Signals and File Descriptors..................................................................... 1368 63.5.1 The pselect() System Call ...................................................................... 1369 63.5.2 The Self-Pipe Trick ............................................................................... 1370 63.6 Summary................................................................................................................ 1373 63.7 Exercises ................................................................................................................ 1374 |