gphoto2-context.h File Reference

Context callback operation functions. More...

#include <stdarg.h>

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Typedefs
typedef _GPContext	GPContext
	The gphoto context structure.
typedef enum _GPContextFeedback	GPContextFeedback
	Return codes that can be returned by progress handling.
typedef void(*)	GPContextIdleFunc (GPContext *context, void *data)
typedef void(*)	GPContextErrorFunc (GPContext *context, const char *format, va_list args, void *data)
typedef void(*)	GPContextStatusFunc (GPContext *context, const char *format, va_list args, void *data)
typedef void(*)	GPContextMessageFunc (GPContext *context, const char *format, va_list args, void *data)
typedef GPContextFeedback(*)	GPContextQuestionFunc (GPContext *context, const char *format, va_list args, void *data)
typedef GPContextFeedback(*)	GPContextCancelFunc (GPContext *context, void *data)
typedef unsigned int(*)	GPContextProgressStartFunc (GPContext *context, float target, const char *format, va_list args, void *data)
typedef void(*)	GPContextProgressUpdateFunc (GPContext *context, unsigned int id, float current, void *data)
typedef void(*)	GPContextProgressStopFunc (GPContext *context, unsigned int id, void *data)
Enumerations
enum	_GPContextFeedback { GP_CONTEXT_FEEDBACK_OK, GP_CONTEXT_FEEDBACK_CANCEL }
	Return codes that can be returned by progress handling. More...
Functions
GPContext *	gp_context_new (void)
	Creates a new context.
void	gp_context_ref (GPContext *context)
void	gp_context_unref (GPContext *context)
	Decrements reference count of a context.
void	gp_context_set_idle_func (GPContext *context, GPContextIdleFunc func, void *data)
void	gp_context_set_progress_funcs (GPContext *context, GPContextProgressStartFunc start_func, GPContextProgressUpdateFunc update_func, GPContextProgressStopFunc stop_func, void *data)
void	gp_context_set_error_func (GPContext *context, GPContextErrorFunc func, void *data)
void	gp_context_set_status_func (GPContext *context, GPContextStatusFunc func, void *data)
void	gp_context_set_question_func (GPContext *context, GPContextQuestionFunc func, void *data)
void	gp_context_set_cancel_func (GPContext *context, GPContextCancelFunc func, void *data)
void	gp_context_set_message_func (GPContext *context, GPContextMessageFunc func, void *data)
void	gp_context_idle (GPContext *context)
	Notify frontend of a brief idle time.
void	gp_context_error (GPContext *context, const char *format,...)
void	gp_context_status (GPContext *context, const char *format,...)
void	gp_context_message (GPContext *context, const char *format,...)
	Print a message to the context.
GPContextFeedback	gp_context_question (GPContext *context, const char *format,...)
	Ask frontend user a question.
GPContextFeedback	gp_context_cancel (GPContext *context)
unsigned int	gp_context_progress_start (GPContext *context, float target, const char *format,...)
	Start progress tracking.
void	gp_context_progress_update (GPContext *context, unsigned int id, float current)
void	gp_context_progress_stop (GPContext *context, unsigned int id)

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Detailed Description

Context callback operation functions.

Author:

Copyright 2001 Lutz Müller <lutz@users.sourceforge.net>

Note:

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

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Typedef Documentation

typedef struct _GPContext GPContext

The gphoto context structure.

This structure allows callback handling, passing error contexts back, progress handling and download cancellation and similar things. It is usually passed around the functions.

typedef enum _GPContextFeedback GPContextFeedback

Return codes that can be returned by progress handling.

An application can return special values back to the libgphoto2 progress callback handling functions. If "Cancel" is selected, libgphoto2 and the camera driver will try to cancel transfer.

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Enumeration Type Documentation

enum _GPContextFeedback

Return codes that can be returned by progress handling.

An application can return special values back to the libgphoto2 progress callback handling functions. If "Cancel" is selected, libgphoto2 and the camera driver will try to cancel transfer.

Enumerator:

GP_CONTEXT_FEEDBACK_OK	Everything ok... proceed.
GP_CONTEXT_FEEDBACK_CANCEL	Please cancel the current transfer if possible.

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Function Documentation

GPContextFeedback gp_context_cancel

(

GPContext *

context

)

gp_context_cancel: : a GPContext

Gives the frontend the possibility to cancel the current operation that is executed in this .

Return value: a GPContextFeedback.

void gp_context_idle

(

GPContext *

context

)

Notify frontend of a brief idle time.

Tells the frontend that it can do other processing at this moment, like refresh the UI. Backends should call this function every time when an interruption of the transfer is possible.

Parameters:

context

a GPContext

void gp_context_message	(	GPContext *	context,
		const char *	format,
			...
	)

Print a message to the context.

This sends a message to the passed context, to be printed by it in some kind of way, but do no other action.

To be used by camera drivers.

Parameters:

	context	A GPContext
	format	A sprintf style format string
	...	variable argument list depending on format string

GPContext* gp_context_new

(

void

)

Creates a new context.

To be used by the frontend.

Returns:

a GPContext.

unsigned int gp_context_progress_start	(	GPContext *	context,
		float	target,
		const char *	format,
			...
	)

Start progress tracking.

This function starts up a new progress tracking for a specified context. Several nested progress reports can happen at once, depending on the backend.

Parameters:

	context	The context in which to start the progress.
	target	The 100% value.
	format	A sprintf style string to print out, including the following variable arguments.

GPContextFeedback gp_context_question	(	GPContext *	context,
		const char *	format,
			...
	)

Ask frontend user a question.

Asks the user a question that he must answer either with "Ok" or "Cancel".

To be used by a camera driver. (So far no camera driver is using it, but this might change later.)

Parameters:

	context	a GPContext
	format	a sprintf format string
	...	variable arguments for format string

Returns:

The user's answer in form of a GPContextFeedback.

void gp_context_ref

(

GPContext *

context

)

Increments the reference count of the context.

Parameters:

context

The context to bump the reference

void gp_context_unref

(

GPContext *

context

)

Decrements reference count of a context.

Decrement the reference count of a context and free if it goes to 0.

Parameters:

context

The context to drop the reference count.

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