1funopen(3) SAORD Documentation funopen(3)
2
6 FunOpen - open a Funtools data file
7
9 #include <funtools.h>
10 Fun FunOpen(char *name, char *mode, Fun ref);
12
14 The FunOpen() routine opens a Funtools data file for reading or append‐
15 ing, or creates a new FITS file for writing. The name argument speci‐
16 fies the name of the Funtools data file to open. You can use IRAF-style
17 bracket notation to specify Funtools Files, Extensions, and Filters. A
18 separate call should be made each time a different FITS extension is
19 accessed:
20 Fun fun;
22 char *iname;
23 ...
24 if( !(fun = FunOpen(iname, "r", NULL)) ){
25 fprintf(stderr, "could not FunOpen input file: %s\n", iname);
26 exit(1);
27 }
28 If mode is "r", the file is opened for reading, and processing is set
30 up to begin at the specified extension. For reading, name can be stdin,
31 in which case the standard input is read.
32 If mode is "w", the file is created if it does not exist, or opened and
34 truncated for writing if it does exist. Processing starts at the begin‐
35 ning of the file. The name can be stdout, in which case the standard
36 output is readied for processing.
37 If mode is "a", the file is created if it does not exist, or opened if
39 it does exist. Processing starts at the end of the file. The name can
40 be stdout, in which case the standard output is readied for processing.
41 When a Funtools file is opened for writing or appending, a previously
43 opened Funtools reference handle can be specified as the third argu‐
44 ment. This handle typically is associated with the input Funtools file
45 that will be used to generate the data for the output data. When a
46 reference file is specified in this way, the output file will inherit
47 the (extension) header parameters from the input file:
48 Fun fun, fun2;
50 ...
51 /* open input file */
52 if( !(fun = FunOpen(argv[1], "r", NULL)) )
53 gerror(stderr, "could not FunOpen input file: %s\n", argv[1]);
54 /* open the output FITS image, inheriting params from input */
55 if( !(fun2 = FunOpen(argv[2], "w", fun)) )
56 gerror(stderr, "could not FunOpen output file: %s\n", argv[2]);
57 Thus, in the above example, the output FITS binary table file will
59 inherit all of the parameters associated with the input binary table
60 extension.
61 A file opened for writing with a Funtools reference handle also inher‐
63 its the selected columns (i.e. those columns chosen for processing
64 using the FunColumnSelect() routine) from the reference file as its
65 default columns. This makes it easy to open an output file in such a
66 way that the columns written to the output file are the same as the
67 columns read in the input file. Of course, column selection can easily
68 be tailored using the FunColumnSelect() routine. In particular, it is
69 easy to merge user-defined columns with the input columns to generate a
70 new file. See the evmerge for a complete example.
71 In addition, when a Funtools reference handle is supplied in a
73 FunOpen() call, it is possible also to specify that all other exten‐
74 sions from the reference file (other than the input extension being
75 processed) should be copied from the reference file to the output file.
76 This is useful, for example, in a case where you are processing a FITS
77 binary table or image and you want to copy all of the other extensions
78 to the output file as well. Copy of other extensions is controlled by
79 adding a "C" or "c" to the mode string of the FunOpen() call of the
80 input reference file. If "C" is specified, then other extensions are
81 always copied (i.e., copy is forced by the application). If "c" is
82 used, then other extensions are copied if the user requests copying by
83 adding a plus sign "+" to the extension name in the bracket specifica‐
84 tion. For example, the funtable program utilizes "c" mode, giving
85 users the option of copying all other extensions:
86 /* open input file -- allow user copy of other extensions */
88 if( !(fun = FunOpen(argv[1], "rc", NULL)) )
89 gerror(stderr, "could not FunOpen input file: %s\n", argv[1]);
90 /* open the output FITS image, inheriting params from input */
91 if( !(fun2 = FunOpen(argv[2], "w", fun)) )
92 gerror(stderr, "could not FunOpen output file: %s\n", argv[2]);
93 Thus, funtable supports either of these command lines:
95 # copy only the EVENTS extension
97 csh> funtable "test.ev[EVENTS,circle(512,512,10)]" foo.ev
98 # copy ALL extensions
99 csh> funtable "test.ev[EVENTS+,circle(512,512,10)]" foo.ev
100 Use of a Funtools reference handle implies that the input file is
102 opened before the output file. However, it is important to note that
103 if copy mode ("c" or "C") is specified for the input file, the actual
104 input file open is delayed until just after the output file is opened,
105 since the copy of prior extensions to the output file takes place while
106 Funtools is seeking to the specified input extension. This implies
107 that the output file should be opened before any I/O is done on the
108 input file or else the copy will fail. Note also that the copy of sub‐
109 sequent extension will be handled automatically by FunClose() if the
110 output file is closed before the input file. Alternatively, it can be
111 done explicitly by FunFlush(), but again, this assumes that the input
112 file still is open.
113 Upon success FunOpen() returns a Fun handle that is used in subsequent
115 Funtools calls. On error, NULL is returned.
116
118 See funtools(n) for a list of Funtools help pages
119version 1.4.2 January 2, 2008 funopen(3)