trusty (3) gd_mconstants.3.gz

NAME

       gd_mconstants — retrieve a list of constant values from a dirfile

SYNOPSIS

       #include <getdata.h>

       const void *gd_mconstants(DIRFILE *dirfile, const char *parent, gd_type_t return_type);

DESCRIPTION

       The  gd_mconstants()  function queries a dirfile(5) database specified by dirfile and returns a read-only
       list of values of the all CONST type metafields for the supplied parent field after  type  conversion  to
       the data type specified by return_type.

       The dirfile argument must point to a valid DIRFILE object previously created by a call to gd_open(3).

       The  array  returned  will be de-allocated by a call to gd_close(3) and should not be de-allocated by the
       caller.  The list returned should not be assumed to be in any particular order, although it is guaranteed
       to  be in the same order as the list of CONST fields returned by gd_mfield_list_by_type(3).  The array is
       unterminated.  The number of values in the array can be obtained from a call to gd_nmfields_by_type(3).

       The caller may not modify any values in the array, or the array itself.   Doing  so  may  cause  database
       corruption.   The  pointer  returned  is guaranteed to be valid until gd_mconstants() is called again, or
       until the array is de-allocated by a call to gd_close(3).

       A corresponding list of names for these fields may be obtained by calling gd_mfield_list_by_type(3).

RETURN VALUE

       Upon successful completion, gd_mconstants() returns a pointer to an array of values containing the values
       of  all  the  CONST  metafields  for  the  supplied  parent  field.   If the parent field has no constant
       metafields, NULL is returned.  On error it returns NULL and sets the dirfile error to  a  non-zero  error
       value.  Possible error values are:

       GD_E_ALLOC
               The library was unable to allocate memory.

       GD_E_BAD_CODE
               The supplied parent field code was not found, or referred to a metafield itself.

       GD_E_BAD_DIRFILE
               The supplied dirfile was invalid.

       GD_E_BAD_TYPE
               The return_type specified was invalid.

       The dirfile error may be retrieved by calling gd_error(3).  A descriptive error string for the last error
       encountered can be obtained from a call to gd_error_string(3).

SEE ALSO

       dirfile(5),    gd_error(3),    gd_error_string(3),    gd_field_list_by_type(3),    gd_nfields_by_type(3),
       gd_mcarrays(3), gd_open(3)