Fri Aug 17 00:17:17 2018

Asterisk developer's documentation


io.h

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00001 /*
00002  * Asterisk -- An open source telephony toolkit.
00003  *
00004  * Copyright (C) 1999 - 2005, Digium, Inc.
00005  *
00006  * Mark Spencer <markster@digium.com>
00007  *
00008  * See http://www.asterisk.org for more information about
00009  * the Asterisk project. Please do not directly contact
00010  * any of the maintainers of this project for assistance;
00011  * the project provides a web site, mailing lists and IRC
00012  * channels for your use.
00013  *
00014  * This program is free software, distributed under the terms of
00015  * the GNU General Public License Version 2. See the LICENSE file
00016  * at the top of the source tree.
00017  */
00018 
00019 /*! \file
00020  * \brief I/O Management (derived from Cheops-NG)
00021  */
00022 
00023 #ifndef _ASTERISK_IO_H
00024 #define _ASTERISK_IO_H
00025 
00026 #include "asterisk/poll-compat.h"
00027 
00028 #if defined(__cplusplus) || defined(c_plusplus)
00029 extern "C" {
00030 #endif
00031 
00032 /*! Input ready */
00033 #define AST_IO_IN    POLLIN
00034 /*! Output ready */
00035 #define AST_IO_OUT   POLLOUT
00036 /*! Priority input ready */
00037 #define AST_IO_PRI   POLLPRI
00038 
00039 /* Implicitly polled for */
00040 /*! Error condition (errno or getsockopt) */
00041 #define AST_IO_ERR   POLLERR
00042 /*! Hangup */
00043 #define AST_IO_HUP   POLLHUP
00044 /*! Invalid fd */
00045 #define AST_IO_NVAL  POLLNVAL
00046 
00047 /*! \brief
00048  * An Asterisk IO callback takes its id, a file descriptor, list of events, and
00049  * callback data as arguments and returns 0 if it should not be
00050  * run again, or non-zero if it should be run again.
00051  */
00052 
00053 struct io_context;
00054 
00055 /*! 
00056  * \brief Creates a context 
00057  * Create a context for I/O operations
00058  * Basically mallocs an IO structure and sets up some default values.
00059  * \return an allocated io_context structure
00060  */
00061 struct io_context *io_context_create(void);
00062 
00063 /*! 
00064  * \brief Destroys a context 
00065  * \param ioc structure to destroy
00066  * Destroy a context for I/O operations
00067  * Frees all memory associated with the given io_context structure along with the structure itself
00068  */
00069 void io_context_destroy(struct io_context *ioc);
00070 
00071 typedef int (*ast_io_cb)(int *id, int fd, short events, void *cbdata);
00072 #define AST_IO_CB(a) ((ast_io_cb)(a))
00073 
00074 /*! 
00075  * \brief Adds an IO context 
00076  * \param ioc which context to use
00077  * \param fd which fd to monitor
00078  * \param callback callback function to run
00079  * \param events event mask of events to wait for
00080  * \param data data to pass to the callback
00081  * Watch for any of revents activites on fd, calling callback with data as
00082  * callback data.  
00083  * \retval a pointer to ID of the IO event
00084  * \retval NULL on failure
00085  */
00086 int *ast_io_add(struct io_context *ioc, int fd, ast_io_cb callback, short events, void *data);
00087 
00088 /*! 
00089  * \brief Changes an IO handler 
00090  * \param ioc which context to use
00091  * \param id
00092  * \param fd the fd you wish it to contain now
00093  * \param callback new callback function
00094  * \param events event mask to wait for
00095  * \param data data to pass to the callback function
00096  * Change an I/O handler, updating fd if > -1, callback if non-null, 
00097  * and revents if >-1, and data if non-null.
00098  * \retval a pointer to the ID of the IO event
00099  * \retval NULL on failure
00100  */
00101 int *ast_io_change(struct io_context *ioc, int *id, int fd, ast_io_cb callback, short events, void *data);
00102 
00103 /*! 
00104  * \brief Removes an IO context 
00105  * \param ioc which io_context to remove it from
00106  * \param id which ID to remove
00107  * Remove an I/O id from consideration  
00108  * \retval 0 on success
00109  * \retval -1 on failure
00110  */
00111 int ast_io_remove(struct io_context *ioc, int *id);
00112 
00113 /*! 
00114  * \brief Waits for IO 
00115  * \param ioc which context to act upon
00116  * \param howlong how many milliseconds to wait
00117  * Wait for I/O to happen, returning after
00118  * howlong milliseconds, and after processing
00119  * any necessary I/O.  
00120  * \return he number of I/O events which took place.
00121  */
00122 int ast_io_wait(struct io_context *ioc, int howlong);
00123 
00124 /*! 
00125  * \brief Dumps the IO array.
00126  * Debugging: Dump everything in the I/O array
00127  */
00128 void ast_io_dump(struct io_context *ioc);
00129 
00130 /*! Set fd into non-echoing mode (if fd is a tty) */
00131 
00132 int ast_hide_password(int fd);
00133 
00134 /*! 
00135  * \brief Restores TTY mode.
00136  * Call with result from previous ast_hide_password
00137  */
00138 int ast_restore_tty(int fd, int oldstatus);
00139 
00140 int ast_get_termcols(int fd);
00141 
00142 #if defined(__cplusplus) || defined(c_plusplus)
00143 }
00144 #endif
00145 
00146 #endif /* _ASTERISK_IO_H */

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