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DPV(3)		       FreeBSD Library Functions Manual			DPV(3)

NAME
     dpv -- dialog progress view library

LIBRARY
     library ``libdpv''

SYNOPSIS
     #include <dpv.h>

     int
     dpv(struct	dpv_config *config, struct dpv_file_node *file_list);

     void
     dpv_free(void);

DESCRIPTION
     The dpv library provides an interface for creating	complex	``gauge'' wid-
     gets for displaying progress on various actions.  The dpv library can
     display progress with one of dialog(3), dialog(1),	or Xdialog(1)
     (x11/xdialog from the ports tree).

     The dpv() config argument properties for configuring global display fea-
     tures:

	   struct dpv_config {
	       uint8_t		keep_tite;     /* Cleaner exit for scripts */
	       enum dpv_display	display_type;  /* Def. DPV_DISPLAY_LIBDIALOG */
	       enum dpv_output	output_type;   /* Default DPV_OUTPUT_NONE */
	       int		debug;	       /* Enable debug on stderr */
	       int		display_limit; /* Files/page. Default -1 */
	       int		label_size;    /* Label	size. Default 28 */
	       int		pbar_size;     /* Mini-progress	size */
	       int		dialog_updates_per_second; /* Default 16 */
	       int		status_updates_per_second; /* Default 2	*/
	       uint16_t		options;       /* Default 0 (none) */
	       char		*title;	       /* Widget title */
	       char		*backtitle;    /* Widget backtitle */
	       char		*aprompt;      /* Append. Default NULL */
	       char		*pprompt;      /* Prefix. Default NULL */
	       char		*msg_done;     /* Default `Done' */
	       char		*msg_fail;     /* Default `Fail' */
	       char		*msg_pending;  /* Default `Pending' */
	       char		*output;       /* Output format	string */
	       const char	*status_solo;  /* dialog(3) solo-status	format.
						* Default DPV_STATUS_SOLO */
	       const char	*status_many;  /* dialog(3) many-status	format.
						* Default DPV_STATUS_MANY */

	       /*
		* Function pointer; action to perform data transfer
		*/
	       int (*action)(struct dpv_file_node *file, int out);
	   };

	   enum	dpv_display {
	       DPV_DISPLAY_LIBDIALOG = 0, /* Use dialog(3) (default) */
	       DPV_DISPLAY_STDOUT,	  /* Use stdout	*/
	       DPV_DISPLAY_DIALOG,	  /* Use spawned dialog(1) */
	       DPV_DISPLAY_XDIALOG,	  /* Use spawned Xdialog(1) */
	   };

	   enum	dpv_output {
	       DPV_OUTPUT_NONE = 0, /* No output (default) */
	       DPV_OUTPUT_FILE,	    /* Read `output' member as file path */
	       DPV_OUTPUT_SHELL,    /* Read `output' member as shell cmd */
	   };

     The options member	of the dpv() config argument is	a mask of bit fields
     indicating	various	processing options.  Possible flags are:

     DPV_TEST_MODE   Enable test mode.	In test	mode, the action() callback of
		     the config	argument is not	called but instead simulated-
		     data is used to drive progress.  Appends ``[TEST MODE]''
		     to	the status line	(to override, set the status_format
		     member of the dpv() config	argument; for example, to
		     DPV_STATUS_DEFAULT).

     DPV_WIDE_MODE   Enable wide mode.	In wide	mode, the length of the
		     aprompt and pprompt members of the	dpv() config argument
		     will bump the width of the	gauge widget.  Prompts wider
		     than the maximum width will wrap (unless using
		     Xdialog(1); see BUGS section below).

     DPV_NO_LABELS   Disables the display of labels associated with each
		     transfer (label_size member of dpv() config argument is
		     ignored).

     DPV_USE_COLOR   Force the use of color even if the	display_type does not
		     support color (USE_COLOR environment variable is
		     ignored).

     DPV_NO_OVERRUN  When enabled, callbacks for the current dpv_file_node are
		     terminated	when action() returns 100 or greater
		     (alleviates the need to change the	status of the current
		     dpv_file_node but may also	cause file truncation if the
		     stream exceeds expected length).

     The file_list argument to dpv() is	a pointer to a ``linked-list'',
     described in <dpv.h>:

	   struct dpv_file_node	{
	       enum dpv_status	  status; /* status of read operation */
	       char		  *msg;	  /* display instead of	"Done/Fail" */
	       char		  *name;  /* name of file to read */
	       char		  *path;  /* path to file */
	       long long	  length; /* expected size */
	       long long	  read;	  /* number units read (e.g., bytes) */
	       struct dpv_file_node *next;/* pointer to	next (end with NULL) */
	   };

     For each of the items in the file_list ``linked-list'' argument, the
     action() callback member of the dpv() config argument is called.  The
     action() function performs	a ``nominal'' action on	the file and return.
     The return	value of int represents	the current progress percentage
     (0-100) for the current file.

     The action() callback provides two	variables for each call.  file pro-
     vides a reference to the current dpv_file_node being processed.  out pro-
     vides a file descriptor where the data goes.

     If	the output member of the dpv() config argument was set to DPV_OUT-
     PUT_NONE (default;	when invoking dpv()), the out file descriptor of
     action() will be zero and can be ignored.	If output was set to DPV_OUT-
     PUT_FILE, out will	be an open file	descriptor to a	file.  If output was
     set to DPV_OUTPUT_SHELL, out will be an open file descriptor to a pipe
     for a spawned shell program.  When	out is greater than zero, write	data
     that has been read	back to	out.

     To	abort dpv(), either from the action() callback or asynchronously from
     a signal handler, two globals are provided	via <dpv.h>:

	   extern int dpv_interrupt; /*	Set to TRUE in interrupt handler */
	   extern int dpv_abort;     /*	Set to true in callback	to abort */

     These globals are not automatically reset and must	be manually main-
     tained.  Do not forget to reset these globals before subsequent invoca-
     tions of dpv() when making	multiple calls from the	same program.

     In	addition, the status member of the action() file argument can be used
     to	control	callbacks for the current file.	 The status member can be set
     to	any of the below from <dpv.h>:

	   enum	dpv_status {
		   DPV_STATUS_RUNNING =	0, /* Running (default)	*/
		   DPV_STATUS_DONE,	   /* Completed	*/
		   DPV_STATUS_FAILED,	   /* Oops, something went wrong */
	   };

     The default status	is zero, DPV_STATUS_RUNNING, which keeps the callbacks
     coming for	the current file().  Setting `file->status' to anything	other
     than DPV_STATUS_RUNNING will cause	dpv() to loop to the next file,
     effecting the next	callback, if any.

     The action() callback is responsible for calculating percentages and
     (recommended) maintaining a dpv global counter so dpv() can display
     throughput	statistics.  Percentages are reported through the int return
     value of the action() callback.  Throughput statistics are	calculated
     from the below global int in <dpv.h>:

	   extern int dpv_overall_read;

     Set this to the number of bytes that have been read for all files.
     Throughput	information is displayed in the	status line (only available
     when using	dialog(3)) at the bottom of the	screen.	 See DPV_DISPLAY_LIB-
     DIALOG above.

     Note that dpv_overall_read	does not have to represent bytes.  For exam-
     ple, the status_format can	be changed to display something	other than
     ``bytes'' and increment dpv_overall_read accordingly (for example,
     counting lines).

     When dpv()	is processing the current file,	the length and read members of
     the action() file argument	are used for calculating the display of	mini
     progress bars (if enabled;	see pbar_size above).  If the length member of
     the current file is less than zero	(indicating an unknown file length), a
     humanize_number(3)	version	of the read member is used instead of a	tradi-
     tional progress bar.  Otherwise a progress	bar is calculated as percent-
     age read to file length.  action()	callback must maintain these member
     values for	mini-progress bars.

     The dpv_free() function performs free(3) on private global	variables ini-
     tialized by dpv().

ENVIRONMENT
     The below environment variables are referenced by dpv:

     DIALOG	Override command string	used to	launch dialog(1) (requires
		DPV_DISPLAY_DIALOG) or Xdialog(1) (requires
		DPV_DISPLAY_XDIALOG); default is either	`dialog' (for
		DPV_DISPLAY_DIALOG) or `Xdialog' (for DPV_DISPLAY_XDIALOG).

     DIALOGRC	If set and non-NULL, path to `.dialogrc' file.

     HOME	If `$DIALOGRC' is either not set or NULL, used as a prefix to
		`.dialogrc' (that is, `$HOME/.dialogrc').

     USE_COLOR	If set and NULL, disables the use of color when	using
		dialog(1) (does	not apply to Xdialog(1)).

     msg_done msg_fail msg_pending
		Internationalization strings for overriding the	default	Eng-
		lish strings `Done', `Fail', and `Pending' respectively.  To
		prevent	their usage, explicitly	set the	msg_done, msg_fail,
		and msg_pending	members	of dpv() config	argument to default
		macros (DPV_DONE_DEFAULT, DPV_FAIL_DEFAULT, and
		DPV_PENDING_DEFAULT) or	desired	values.

FILES
     $HOME/.dialogrc

SEE ALSO
     dialog(1),	Xdialog(1), dialog(3)

HISTORY
     The dpv library first appeared in FreeBSD 10.2.

AUTHORS
     Devin Teske <dteske@FreeBSD.org>

BUGS
     Xdialog(1), when given both `--title title' (see above `title' member of
     struct dpv_config)	and `--backtitle backtitle' (see above `backtitle'
     member of struct dpv_config), displays the	backtitle in place of the
     title and vice-versa.

     Xdialog(1)	does not wrap long prompt texts	received after initial launch.
     This is a known issue with	the `--gauge' widget in	Xdialog(1).  Embed
     escaped newlines within prompt text to force line breaks.

     dialog(1) does not	display	the first character after a series of escaped
     escape-sequences (for example, ``\\n'' produces ``\'' instead of ``\n'').
     This is a known issue with	dialog(1) and does not affect dialog(3)	or
     Xdialog(1).

     If	an application ignores USE_COLOR when set and NULL before calling
     dpv() with	color escape sequences anyway, dialog(3) and dialog(1) may not
     render properly.  Workaround is to	detect when USE_COLOR is set and NULL
     and either	not use	color escape sequences at that time or use unsetenv(3)
     to	unset USE_COLOR, forcing interpretation	of color sequences.  This does
     not effect	Xdialog(1), which renders the color escape sequences as	plain
     text.  See	``embedded "\Z"	sequences'' in dialog(1) for additional	infor-
     mation.

FreeBSD	Ports 11.2		March 13, 2018		    FreeBSD Ports 11.2

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | ENVIRONMENT | FILES | SEE ALSO | HISTORY | AUTHORS | BUGS

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