NAME

       gd_get_carray, gd_get_carray_slice — retrieve CARRAY data from a dirfile database

SYNOPSIS

       #include <getdata.h>

       int gd_get_carray_slice(DIRFILE *dirfile, const char *field_code, unsigned int start,
              size_t len, gd_type_t return_type, void *data_out);

       int gd_get_carray(DIRFILE *dirfile, const char *field_code, gd_type_t return_type, void
              *data_out);

DESCRIPTION

       The  gd_get_carray_slice() function queries a dirfile(5) database specified by dirfile for
       the CARRAY scalar array field_code, which may contain a representation suffix.   The  data
       in  the  field  is  converted to the data type specified by return_type, and stored in the
       user-supplied buffer data_out.  The first element of the field stored is given  by  start,
       and  the  number of elements stored is given by len.  The gd_get_carray() function behaves
       similarly, except it returns the entire field.

       The dirfile argument must point to a valid DIRFILE object previously created by a call  to
       gd_open(3).   The  argument  data_out  must point to a valid memory location of sufficient
       size to hold all the requested data of the return type specified.  The number of  elements
       returned   by  gd_get_carray()  may  be  obtained  by  calling  gd_carray_len(3).   Unlike
       gd_getdata(3), calling gd_get_carray_slice() never results in a short read; attempting  to
       read past the end of the CARRAY will result in an error, and no data will be returned.

       The  return_type  argument  should  be  one  of the following symbols, which indicates the
       desired return type of the data:

              GD_UINT8   unsigned 8-bit integer

              GD_INT8    signed (two's complement) 8-bit integer

              GD_UINT16  unsigned 16-bit integer

              GD_INT16   signed (two's complement) 16-bit integer

              GD_UINT32  unsigned 32-bit integer

              GD_INT32   signed (two's complement) 32-bit integer

              GD_UINT64  unsigned 64-bit integer

              GD_INT64   signed (two's complement) 64-bit integer

              GD_FLOAT32 IEEE-754 standard 32-bit single precision floating point number

              GD_FLOAT64 IEEE-754 standard 64-bit double precision floating point number

              GD_COMPLEX64
                         C99-conformant 64-bit single precision complex number

              GD_COMPLEX128
                         C99-conformant 128-bit double precision complex number

              GD_NULL    the null type: the  database  is  queried  as  usual,  but  no  data  is
                         returned.  In this case, data_out is ignored and may be NULL.

       The  return  type  of the field need not be the same as the type of the data stored in the
       database.  Type conversion will be performed as necessary to return  the  requested  type.
       If  the field_code does not indicate a representation, but conversion from a complex value
       to a purely real one is required, only the real portion of the requested  vector  will  be
       returned.

RETURN VALUE

       On  success, gd_get_carray() and gd_get_carray_slice() return zero.  On error, they return
       -1 and set the dirfile error to a non-zero value.  Possible error values are:

       GD_E_BAD_CODE
               The field specified by field_code was not found in the database.

       GD_E_BAD_DIRFILE
               An invalid dirfile was supplied.

       GD_E_BAD_FIELD_TYPE
               The supplied field_code referred to a field of a  type  other  than  CARRAY.   The
               caller should use gd_getdata(3), gd_get_constant(3), or gd_get_string(3) instead.

       GD_E_BAD_REPR
               The representation suffix specified in field_code, or in one of the field codes it
               uses for input, was invalid.

       GD_E_BAD_TYPE
               An invalid return_type was specified.

       GE_E_BOUNDS
               A request for data beyond the end of the field was made.

       GD_E_INTERNAL_ERROR
               An internal error occurred in the library while trying to perform the task.   This
               indicates a bug in the library.  Please report the incident to the maintainer.

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

SEE ALSO

       dirfile(5),    gd_carray_len(3),    gd_carrays(3),    gd_error(3),     gd_error_string(3),
       gd_get_constant(3), gd_open(3), gd_put_carray_slice(3)