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

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.
Typedefs
typedef struct _Ecore_Fd_Handler	Ecore_Fd_Handler
typedef Eina_Bool(*	Ecore_Fd_Cb )(void data, Ecore_Fd_Handler fd_handler)
typedef void(*	Ecore_Fd_Prep_Cb )(void data, Ecore_Fd_Handler fd_handler)
typedef Eina_Bool(*	Ecore_Win32_Handle_Cb )(void data, Ecore_Win32_Handler wh)

Typedef Documentation

Ecore_Fd_Cb Ecore_Fd_Cb

A callback used by an Ecore_Fd_Handler.

Examples:: ecore_fd_handler_gnutls_example.c.

typedef struct _Ecore_Fd_Handler Ecore_Fd_Handler

A handle for Fd handlers

Ecore_Fd_Prep_Cb Ecore_Fd_Prep_Cb

A callback used by an Ecore_Fd_Handler.

Ecore_Win32_Handle_Cb Ecore_Win32_Handle_Cb

A callback used by an Ecore_Win32_Handler.

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

Function Documentation

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.

Since :: 2.3

Examples:: ecore_fd_handler_example.c.

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.

Since :: 2.3

Examples:: ecore_fd_handler_gnutls_example.c.

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.

Since :: 2.3

Examples:: ecore_evas_basics_example.c, ecore_exe_example_child.c, ecore_fd_handler_example.c, and ecore_fd_handler_gnutls_example.c.

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.

Since :: 2.3

Examples:: ecore_fd_handler_example.c.

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.

Since :: 2.3

Examples:: ecore_fd_handler_example.c.

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 (EFL) :: 1.7

Since :: 2.3

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.

Since :: 2.3

Examples:: ecore_fd_handler_example.c.

Functions

Typedefs

Typedef Documentation

Enumeration Type Documentation

Function Documentation