Ecore_FD_Handler_Group(3)

NAME
Ecore_FD_Handler_Group - File Descriptor Handling Functions

 - Definition for functions that deal with file descriptor handlers.

SYNOPSIS

  Typedefs
typedef struct _Ecore_Fd_Handler Ecore_Fd_Handler
A handle for Fd handlers.
typedef enum _Ecore_Fd_Handler_Flags Ecore_Fd_Handler_Flags
typedef Eina_Bool(* Ecore_Fd_Cb) (void *data, Ecore_Fd_Handler *fd_handler)
A callback used by an Ecore_Fd_Handler.
typedef void(* Ecore_Fd_Prep_Cb) (void *data, Ecore_Fd_Handler *fd_handler)
A callback used by an Ecore_Fd_Handler.
typedef Eina_Bool(* Ecore_Win32_Handle_Cb) (void *data, Ecore_Win32_Handler *wh)
A callback used by an Ecore_Win32_Handler.

  Enumerations
enum _Ecore_Fd_Handler_Flags { ECORE_FD_READ = 1, ECORE_FD_WRITE = 2, ECORE_FD_ERROR = 4, ECORE_FD_ALWAYS = 8 }
What to monitor the file descriptor for: reading, writing or error.

  Functions
Ecore_Fd_Handler * ecore_main_fd_handler_add (int fd, Ecore_Fd_Handler_Flags flags, Ecore_Fd_Cb func, const void *data, Ecore_Fd_Cb buf_func, const void *buf_data)
Adds a callback for activity on the given file descriptor.
Ecore_Fd_Handler * ecore_main_fd_handler_file_add (int fd, Ecore_Fd_Handler_Flags flags, Ecore_Fd_Cb func, const void *data, Ecore_Fd_Cb buf_func, const void *buf_data)
Adds a callback for activity on the given file descriptor.
void ecore_main_fd_handler_prepare_callback_set (Ecore_Fd_Handler *fd_handler, Ecore_Fd_Prep_Cb func, const void *data)
Sets the prepare callback with data for a given Ecore_Fd_Handler.
void * ecore_main_fd_handler_del (Ecore_Fd_Handler *fd_handler)
Marks an FD handler for deletion.
int ecore_main_fd_handler_fd_get (Ecore_Fd_Handler *fd_handler)
Retrieves the file descriptor that the given handler is handling.
Eina_Bool ecore_main_fd_handler_active_get (Ecore_Fd_Handler *fd_handler, Ecore_Fd_Handler_Flags flags)
Gets which flags are active on an FD handler.
void ecore_main_fd_handler_active_set (Ecore_Fd_Handler *fd_handler, Ecore_Fd_Handler_Flags flags)
Sets what active streams the given FD handler should be monitoring.
Ecore_Win32_Handler * ecore_main_win32_handler_add (void *h, Ecore_Win32_Handle_Cb func, const void *data)
Creates a Ecore_Win32_Handler object and add it to the win32_handlers list.
void * ecore_main_win32_handler_del (Ecore_Win32_Handler *win32_handler)
Sets Ecore_Win32_Handler object to delete state.

Detailed Description

Definition for functions that deal with file descriptor handlers. File descriptor handlers facilitate reading, writing and checking for errors without blocking the program or doing expensive pooling. This can be used to monitor a socket, pipe, or other stream for which an FD can be had.

Warning
    File descriptor handlers can't be used to monitor for file creation, modification or deletion, see Ecore_File - Files and directories convenience functions for this.

One common FD to be monitored is the standard input(stdin), monitoring it for reading requires a single call:

static Eina_Bool
_my_cb_func(void *data, Ecore_Fd_Handler *handler)
{
   char c;
   scanf("%c", &c); //Guaranteed not to block
   ... do stuff with c ...
}
ecore_main_fd_handler_add(STDIN_FILENO, ECORE_FD_READ, _my_cb_func, NULL, NULL, NULL);

When using a socket, pipe or other stream it's important to remember that errors may occur and as such to monitor not only for reading/writing but also for errors using the ECORE_FD_ERROR flag.

Example of use of a file descriptor handler:
•   ecore fd handlers - Monitoring file descriptors

Enumeration Type Documentation

  enum _Ecore_Fd_Handler_Flags
What to monitor the file descriptor for: reading, writing or error.
Enumerator
ECORE_FD_READ
    Fd Read mask.
ECORE_FD_WRITE
    Fd Write mask.
ECORE_FD_ERROR
    Fd Error mask.
ECORE_FD_ALWAYS
    Fd Always mask - DO NOT USE!

Function Documentation

  Ecore_Fd_Handler* ecore_main_fd_handler_add (int fd, Ecore_Fd_Handler_Flags flags, Ecore_Fd_Cb func, const void * data, Ecore_Fd_Cb buf_func, const void * buf_data)
Adds a callback for activity on the given file descriptor.
Parameters
    fd The file descriptor to watch.
    flags To monitor it for reading use ECORE_FD_READ, for writing ECORE_FD_WRITE, and for error ECORE_FD_ERROR. Values by |(ored).
    func The callback function.
    data The data to pass to the callback.
    buf_func The function to call to check if any data has been buffered and already read from the fd. May be NULL.
    buf_data The data to pass to the buf_func function.
Returns
    A fd handler handle on success, NULL otherwise.
func will be called during the execution of The Ecore Main Loop when the file descriptor is available for reading, writing, or there has been an error(depending on the given flags).
When func returns ECORE_CALLBACK_CANCEL, it indicates that the handler should be marked for deletion (identical to calling ecore_main_fd_handler_del).
Warning
    buf_func is meant for internal use only and should be avoided.
The return value of buf_func has a different meaning, when it returns ECORE_CALLBACK_CANCEL, it indicates that func shouldn't be called, and when it returns ECORE_CALLBACK_RENEW it indicates func should be called. The return value of buf_func will not cause the FD handler to be deleted.
buf_func is called during event loop handling to check if data that has been read from the file descriptor is in a buffer and is available to read. Some systems, notably xlib, handle their own buffering, and would otherwise not work with select(). These systems should use a buf_func. This is a most annoying hack, only ecore_x uses it, so refer to that for an example.
Warning
    This function should not be used for monitoring 'normal' files, like text files.
Examples
ecore_con_client_example.c, ecore_evas_basics_example.c, ecore_exe_example_child.c, ecore_fd_handler_example.c, and ecore_fd_handler_gnutls_example.c.
References EINA_MAIN_LOOP_CHECK_RETURN_VAL.
Referenced by ecore_drm_device_open(), ecore_fb_input_device_listen(), ecore_pipe_full_add(), ecore_pipe_thaw(), and ecore_wl2_display_create().

  Ecore_Fd_Handler* ecore_main_fd_handler_file_add (int fd, Ecore_Fd_Handler_Flags flags, Ecore_Fd_Cb func, const void * data, Ecore_Fd_Cb buf_func, const void * buf_data)
Adds a callback for activity on the given file descriptor.
Parameters
    fd The file descriptor to watch.
    flags To monitor it for reading use ECORE_FD_READ, for writing ECORE_FD_WRITE, and for error ECORE_FD_ERROR. Values by |(ored).
    func The callback function.
    data The data to pass to the callback.
    buf_func The function to call to check if any data has been buffered and already read from the fd. May be NULL.
    buf_data The data to pass to the buf_func function.
Returns
    A fd handler handle on success, NULL otherwise.
This function is identical to ecore_main_fd_handler_add, except that it supports regular files.
Warning
    This function should ONLY be called with ECORE_FD_ERROR, otherwise it will call the fd handler constantly.
    Do not use this function unless you know what you are doing.
Since
    1.7
References EINA_MAIN_LOOP_CHECK_RETURN_VAL.
Referenced by ecore_wl2_offer_receive(), and eeze_mount_tabs_watch().

  void ecore_main_fd_handler_prepare_callback_set (Ecore_Fd_Handler * fd_handler, Ecore_Fd_Prep_Cb func, const void * data)
Sets the prepare callback with data for a given Ecore_Fd_Handler.
Parameters
    fd_handler The fd handler
    func The prep function
    data The data to pass to the prep function
This function will be called prior to any fd handler's callback function (even the other fd handlers), before entering the main loop select function.
Note
    Once a prepare callback is set for a fd handler, it cannot be changed. You need to delete the fd handler and create a new one, to set another callback.
    You probably don't need this function. It is only necessary for very uncommon cases that need special behavior.
Examples
ecore_fd_handler_example.c.
References eina_list_append(), eina_list_data_find(), and EINA_MAIN_LOOP_CHECK_RETURN.
Referenced by ecore_wl2_display_create().

  void* ecore_main_fd_handler_del (Ecore_Fd_Handler * fd_handler)
Marks an FD handler for deletion.
Parameters
    fd_handler The FD handler.
Returns
    The data pointer set using ecore_main_fd_handler_add, for fd_handler on success, NULL otherwise. This function marks an fd handler to be deleted during an iteration of the main loop. It does NOT close the associated fd!
Warning
    If the underlying fd is already closed ecore may complain if the main loop is using epoll internally, and also in some rare cases this may cause crashes and instability. Remember to delete your fd handlers before the fds they listen to are closed.
Examples
ecore_fd_handler_example.c.
References EINA_MAIN_LOOP_CHECK_RETURN_VAL.
Referenced by ecore_avahi_del(), eeze_mount_tabs_unwatch(), eeze_udev_watch_del(), and elput_input_shutdown().

  int ecore_main_fd_handler_fd_get (Ecore_Fd_Handler * fd_handler)
Retrieves the file descriptor that the given handler is handling.
Parameters
    fd_handler The given FD handler.
Returns
    The file descriptor the handler is watching.
Examples
ecore_fd_handler_example.c.
References EINA_MAIN_LOOP_CHECK_RETURN_VAL.
Referenced by ecore_input_joystick_name_get().

  Eina_Bool ecore_main_fd_handler_active_get (Ecore_Fd_Handler * fd_handler, Ecore_Fd_Handler_Flags flags)
Gets which flags are active on an FD handler.
Parameters
    fd_handler The given FD handler.
    flags The flags, ECORE_FD_READ, ECORE_FD_WRITE or ECORE_FD_ERROR to query.
Returns
    EINA_TRUE if any of the given flags are active, EINA_FALSE otherwise.
Examples
ecore_fd_handler_example.c.
References ECORE_FD_ERROR, ECORE_FD_READ, ECORE_FD_WRITE, EINA_FALSE, EINA_MAIN_LOOP_CHECK_RETURN_VAL, and EINA_TRUE.

  void ecore_main_fd_handler_active_set (Ecore_Fd_Handler * fd_handler, Ecore_Fd_Handler_Flags flags)
Sets what active streams the given FD handler should be monitoring.
Parameters
    fd_handler The given FD handler.
    flags The flags to be watching.
Examples
ecore_fd_handler_gnutls_example.c.
References ERR.
Referenced by ecore_wl2_display_flush().

  Ecore_Win32_Handler* ecore_main_win32_handler_add (void * h, Ecore_Win32_Handle_Cb func, const void * data)
Creates a Ecore_Win32_Handler object and add it to the win32_handlers list.
Parameters
    h The win32 handler.
    func The function to add as a callback.
    data The data to pass to the callback when it is called.
Examples
ecore_exe_example_child.c.

  void* ecore_main_win32_handler_del (Ecore_Win32_Handler * win32_handler)
Sets Ecore_Win32_Handler object to delete state. The handler will be deleted in the _ecore_main_win32_handlers_cleanup function.
Parameters
    win32_handler The Ecore_Win32_Handler object.

Author
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