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9gd_nframes(3)                       GETDATA                      gd_nframes(3)
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NAME

14       gd_nframes — report the size of a Dirfile
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SYNOPSIS

18       #include <getdata.h>
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20       off_t gd_nframes(DIRFILE *dirfile);
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DESCRIPTION

24       The  gd_nframes()  function  queries a dirfile(5) database specified by
25       dirfile and returns the number of frames in the database.   Since  dif‐
26       ferent  fields  may  have differing number of frames, the Dirfile Stan‐
27       dards (see dirfile(5)) dictate that the number of frames in  the  data‐
28       base  is  defined  to be equal to the number of frames in the reference
29       field defined by the /REFERENCE directive (see  dirfile-format(5))  or,
30       if no such reference field is defined, by the first raw field specified
31       in the format specification.
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33       If no vector fields are defined in the database,  gd_nframes()  returns
34       zero and succeeds.
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36       The  dirfile  argument  must point to a valid DIRFILE object previously
37       created by a call to gd_open(3).
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RETURN VALUE

41       Upon successful completion, gd_nframes() returns the number  of  frames
42       in  the dirfile, which is never negative.  On error, it returns a nega‐
43       tive-valued error code.  Possible error codes are:
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45       GD_E_ALLOC
46               The library was unable to allocate memory.
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48       GD_E_BAD_DIRFILE
49               The supplied dirfile was invalid.
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51       GD_E_IO An I/O error occurred while determining the number  of  samples
52               in the data file associated with the reference field.
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54       GD_E_UNKNOWN_ENCODING
55               The  number  of samples available for the reference field could
56               not be determined because the encoding used to store the refer‐
57               ence field's data file was not understood.
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59       GD_E_UNSUPPORTED
60               GetData  does not support determining the number of samples for
61               the encoding of of the data file associated with the  reference
62               field.
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64       The  error  code  is  also  stored in the DIRFILE object and may be re‐
65       trieved after this function returns by calling gd_error(3).  A descrip‐
66       tive   error   string   for  the  error  may  be  obtained  by  calling
67       gd_error_string(3).
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HISTORY

71       The get_nframes() function appeared in GetData-0.3.0.
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73       In GeData-0.7.0, this function was renamed to gd_nframes().
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SEE ALSO

77       dirfile(5),  dirfile-encoding(5),  gd_open(3),  gd_bof(3),   gd_eof(3),
78       gd_error(3), gd_error_string(3)
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82Version 0.10.0                 25 December 2016                  gd_nframes(3)
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