PRO FXBFIND,P1,KEYWORD,COLUMNS,VALUES,N_FOUND,DEFAULT, $                    COMMENTS=COMMENTS;+; NAME: ;	FXBFIND; Purpose     : ;	Find column keywords in a FITS binary table header.; Explanation : ;	Finds the value of a column keyword for all the columns in the binary;	table for which it is set.  For example,;;		FXBFIND, UNIT, 'TTYPE', COLUMNS, VALUES, N_FOUND;;	Would find all instances of the keywords TTYPE1, TTYPE2, etc.  The;	array COLUMNS would contain the column numbers for which a TTYPEn;	keyword was found, and VALUES would contain the values.  N_FOUND would;	contain the total number of instances found.;; Use         : ;	FXBFIND, [UNIT or HEADER], KEYWORD, COLUMNS, VALUES, N_FOUND;		[, DEFAULT ]; Inputs      : ;	Either UNIT or HEADER must be passed.;;	UNIT	= Logical unit number of file opened by FXBOPEN.;	HEADER	= FITS binary table header.;	KEYWORD	= Prefix to a series of FITS binary table column keywords.  The;		  keywords to be searched for are formed by combining this;		  prefix with the numbers 1 through the value of TFIELDS in the;		  header.; Opt. Inputs : ;	DEFAULT	= Default value to use for any column keywords that aren't;		  found.  If passed, then COLUMNS and VALUES will contain;		  entries for every column.  Otherwise, COLUMNS and VALUES only;		  contain entries for columns where values were found.; Outputs     : ;	COLUMNS	= Array containing the column numbers for which values of the;		  requested keyword series were found.;	VALUES	= Array containing the found values.;	N_FOUND	= Number of values found.  The value of this parameter is;		  unaffected by whether or not DEFAULT is passed.; Opt. Outputs: ;	None.; Output Keywords    : ;      COMMENTS = Comments associated with each keyword, if any; Calls       : ;	FXBFINDLUN, FXPAR; Common      : ;	Uses common block FXBINTABLE--see "fxbintable.pro" for more;	information.; Restrictions: ;	If UNIT is passed, then the file must have been opened with FXBOPEN.;	If HEADER is passed, then it must be a legal FITS binary table header.;;	The type of DEFAULT must be consistent with the values of the requested;	keywords, i.e. both most be either of string or numerical type.;;	The KEYWORD prefix must not have more than five characters to leave;	room for the three digits allowed for the column numbers.;; Side effects: ;	None.; Category    : ;	Data Handling, I/O, FITS, Generic.; Prev. Hist. : ;	William Thompson, Feb. 1992.; Written     : ;	William Thompson, GSFC, February 1992.; Modified    : ;	Version 1, William Thompson, GSFC, 12 April 1993.;		Incorporated into CDS library.; Version     : ;	Version 1, 12 April 1993.;       Vectorized implementation improves performance, CM 18 Nov 1999;       Added COMMENTS keyword CM Nov 2003;-;@fxbintable	ON_ERROR,2;;  Check the number of parameters.;	IF N_PARAMS() LT 5 THEN MESSAGE,	$		'Syntax:  FXBFIND,[UNIT/HEADER],KEYWORD,COLUMNS,VALUES,' + $		'N_FOUND [,DEFAULT]';;  Get the header.;	IF N_ELEMENTS(P1) EQ 1 THEN BEGIN		ILUN = FXBFINDLUN(P1)		HEADER = HEAD[*,ILUN]	END ELSE HEADER = P1;;  Get the value of TFIELDS from HEADER.;	TFIELDS0 = FXPAR(HEADER,'TFIELDS')	IF TFIELDS0 EQ 0 THEN MESSAGE,'No columns found in HEADER';;  Extract the keyword values all in one pass;                KEYVALUES = FXPAR(HEADER, STRTRIM(KEYWORD,2)+'*', $                          COMMENT=COMMENT_STRS, DATATYPE=DEFAULT)        N_FOUND = 0L;;  INDEX is used as an array index to fill in the final output;        IF !ERR GE 0 THEN BEGIN            N_FOUND = N_ELEMENTS(KEYVALUES)            INDEX   = LINDGEN(N_FOUND)        ENDIF;;  If a default was given, then we are a little more careful to ;  reproduce the correct number of values.;        IF N_ELEMENTS(DEFAULT) GT 0 THEN BEGIN            ;; If no values were found we need to fill KEYVALUES with            ;; *something*.            IF !ERR LE 0 THEN KEYVALUES = DEFAULT            COLUMNS  = LINDGEN(TFIELDS0) + 1            ;; Make an array with the number of columns in the table            SZ_VALUE = SIZE(KEYVALUES[0])            VALUES   = MAKE_ARRAY(TFIELDS0, TYPE=SZ_VALUE[1], VALUE=DEFAULT)            COMMENTS = STRARR(TFIELDS0)            ;; Fill the columns which had this keyword            IF N_FOUND GT 0 THEN BEGIN                VALUES[INDEX] = KEYVALUES                COMMENTS[INDEX] = COMMENT_STRS            ENDIF        ENDIF ELSE BEGIN;;  If no default was given, we can simply return the values returned;  by FXPAR.;            IF N_FOUND GT 0 THEN BEGIN                COLUMNS = INDEX + 1                VALUES  = KEYVALUES                COMMENTS = COMMENT_STRS            ENDIF        ENDELSE        RETURN            	END