NAME

       gd_put_constant — retrieve a scalar constant from a dirfile database

SYNOPSIS

       #include <getdata.h>

       int gd_put_constant(DIRFILE *dirfile, const char *field_code, gd_type_t data_type, const void *data_in);

DESCRIPTION

       The  gd_put_constant()  function  queries  a  dirfile(5) database specified by dirfile and sets the CONST
       scalar field_code , which may not contain a representation suffix, to the  value  specified  in  data_in,
       which should be of the type indicated by data_type.

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

       The data_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 or GD_FLOAT
                         IEEE-754 standard 32-bit single precision floating point number

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

       The  data type of the supplied value need not be the same as the type of the storage type of the constant
       in the database.  Type conversion will be performed as necessary to return the requested type.  The argu‐
       ment data_out must point to valid data type of the specified type.

       Because constant values are stored in the dirfile metadata, the new value of field_code won't be  written
       to disk until the dirfile metadata is flushed with gd_metaflush(3), or until the dirfile is closed.

RETURN VALUE

       On success, gd_put_constant() returns zero.  On error, it returns -1 and sets the dirfile error to a non-
       zero value.  Possible error values are:

       GD_E_ACCMODE
               The specified dirfile was opened read-only.

       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 type other than CONST.  The caller should use
               gd_putdata(3), gd_put_carray(3), or gd_put_string(3) instead.

       GD_E_BAD_REPR
               The representation suffix specified in field_code was not recognised.

       GD_E_BAD_TYPE
               An invalid data_type was specified.

       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.

       GD_E_PROTECTED
               The fragment containing the constant was protected from change.

       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_metaflush(3), gd_get_constant(3), gd_error(3), gd_error_string(3), gd_open(3), gd_put_car‐
       ray(3), gd_put_string(3), gd_putdata(3)

Version 0.7.0                                    4 November 2010                              gd_put_constant(3)