get_mconstants(3)

1get_mconstants(3)                   GETDATA                  get_mconstants(3)
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NAME

6       get_mconstants — retrieve a list of constant values from a dirfile
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SYNOPSIS

9       #include <getdata.h>
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11       const void *get_mconstants(DIRFILE *dirfile, gd_type_t return_type,
12              const char *parent);
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DESCRIPTION

15       The get_mconstants() function queries a dirfile(5)  database  specified
16       by dirfile and returns a read-only list of values of the all CONST type
17       metafields for the supplied parent field after type conversion  to  the
18       data type specified by return_type.
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20       The  dirfile  argument  must point to a valid DIRFILE object previously
21       created by a call to dirfile_open(3).
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23       The array returned will be de-allocated by a call  to  dirfile_close(3)
24       and should not be de-allocated by the caller.  The list returned should
25       not be assumed to be in any particular order, although it is guaranteed
26       to  be  in  the  same  order  as  the  list of CONST fields returned by
27       get_mfield_list_by_type(3).  The array is unterminated.  The number  of
28       values   in   the  array  can  be  obtained  from  a  call  to  get_nm‐
29       fields_by_type(3).
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31       The caller may not modify any values in the array, or the array itself.
32       Doing  so may cause database corruption.  The pointer returned is guar‐
33       anteed to be valid until get_mconstants() is called again with the same
34       arguments,   or   until   the   array  is  deallocated  by  a  call  to
35       dirfile_close(3).
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37       A corresponding list of names for these fields may be obtained by call‐
38       ing get_mfield_list_by_type(3).
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RETURN VALUE

42       Upon  successful  completion,  get_mconstants() returns a pointer to an
43       array of values containing the values of all the CONST  metafields  for
44       the  supplied  parent  field.   If  the  parent  field  has no constant
45       metafields, NULL is returned.  On error it returns NULL  and  sets  the
46       dirfile error to a non-zero error value.  Possible error values are:
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48       GD_E_ALLOC
49               The library was unable to allocate memory.
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51       GD_E_BAD_CODE
52               The  supplied parent field code was not found, or referred to a
53               metafield itself.
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55       GD_E_BAD_DIRFILE
56               The supplied dirfile was invalid.
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58       GD_E_BAD_TYPE
59               The return_type specified was invalid.
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61       The dirfile error may be retrieved by calling get_error(3).  A descrip‐
62       tive error string for the last error encountered can be obtained from a
63       call to get_error_string(3).
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NAME

SYNOPSIS

DESCRIPTION

RETURN VALUE

SEE ALSO