gd_put_constant(3)						      GETDATA							gd_put_constant(3)

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 con-
       tain 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 argument 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_carray(3), gd_put_string(3), gd_putda-
       ta(3)

Version 0.7.0							  4 November 2010						gd_put_constant(3)