xenial (3) gd_get_carray_slice.3.gz

NAME

       gd_get_carray,  gd_get_carray_slice,  gd_get_constant  —  retrieve  CONST  or  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);

       int gd_get_constant(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 CONST or
       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,  as  if
       gd_get_carray_slice() were called with start equal to zero  and  len  equal  to  the  value  returned  by
       gd_carray_len(3).   The  gd_get_constant()  function  is equivalent to calling gd_get_carray_slice() with
       start equal to zero and len equal to one.

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

       GD_E_ALLOC
               The library was unable to allocate memory.

       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 was not a CONST nor CARRAY.   The  caller  should  use  gd_getdata(3)  or
               gd_get_string(3) instead.

       GD_E_BAD_TYPE
               An invalid return_type was specified.

       GD_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)