gd_get_constant(3) [debian man page]

gd_get_constant(3)						      GETDATA							gd_get_constant(3)

NAME

       gd_get_constant -- retrieve a scalar constant from a dirfile database

SYNOPSIS

       #include <getdata.h>

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

DESCRIPTION

       The gd_get_constant() function queries a dirfile(5) database specified by dirfile for the CONST scalar field_code, which may contain a rep-
       resentation suffix.  The constant is converted to the data type specified by return_type, and stored in the user-supplied buffer data_out.

       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 a value of the return type specified.

       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 constant 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_constant() returns zero.  On error, it returns -1 and sets 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 CONST.  The caller should use gd_getdata(3), or gd_get_string(3)
	       instead.

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

       GD_E_BAD_TYPE
	       An invalid return_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.

       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_open(3), gd_error(3), gd_error_string(3), gd_get_carray(3), gd_constants(3), gd_put_constant(3)

Version 0.7.0							  3 Novmeber 2010						gd_get_constant(3)

gd_native_type(3)						      GETDATA							 gd_native_type(3)

NAME

       gd_native_type -- returns the native data type of a field in a dirfile

SYNOPSIS

       #include <getdata.h>

       gd_type_t gd_native_type(DIRFILE *dirfile, const char *field_code);

DESCRIPTION

       The  gd_native_type() function queries a dirfile(5) database specified by dirfile and returns the native data type of the field field_code,
       which may contain a representation suffix.

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

       The native data type of a field of a given entry type is calculated as:

       BIT or INDEX Entry:
	      GD_UINT64;

       CONST or CARRAY Entry:
	      the data type of the field;

       LINCOM or POLYNOM Entry:
	      if any of the scalar parameters is complex valued, or if the native data type of any of the input fields is complex valued:  GD_COM-
	      PLEX128, otherwise: GD_FLOAT64;

       LINTERP Entry:
	      if the look-up table is complex valued: GD_COMPLEX128, otherwise: GD_FLOAT64;

       MULTIPLY or DIVIDE Entry:
	      if either input field is complex valued: GD_COMPLEX128, otherwise: GD_FLOAT64;

       PHASE Entry:
	      the native data type of the input field;

       RAW Entry:
	      the data type of the raw data on disk;

       RECIP Entry:
	      if the dividend or the native data type of the input field is complex valued: GD_COMPLEX128, otherwise: GD_FLOAT64;

       SBIT Entry:
	      GD_INT64;

       STRING Entry:
	      GD_NULL.

       Furthermore,  if the supplied field_code contains a representation suffix, and the native data type of the field is complex valued, the na-
       tive type returned will be the corresponding real valued type.

RETURN VALUE

       Upon successful completion, gd_native_type() returns the native data type of the field code specified.  This will be one of the symbols:

	      GD_NULL, GD_UINT8, GD_INT8, GD_UINT16, GD_INT16, GD_UINT32, GD_INT32, GD_FLOAT32, GD_FLOAT64, GD_COMPLEX64, GD_COMPLEX128.

       The meanings of these symbols are explained in the gd_getdata(3) manual page.  On error, it returns GD_UNKNOWN and sets the  dirfile  error
       to a non-zero error value.  Possible error values are:

       GD_E_BAD_CODE
	       The field specified by field_code or one of the fields it uses as input was not found in the database.

       GD_E_BAD_DIRFILE
	       The supplied dirfile was invalid.

       GD_E_BAD_REPR
	       The representation suffix specified in field_code, or in one of its input fields, was not recognised.

       GD_E_BAD_SCALAR
	       A non-literal scalar used in the definition of the field or one of its inputs was not found, or was not a CONST or CARRAY field.

       GD_E_DIMENSION
	       A scalar field was found where a vector field was expected.

       GD_E_OPEN_LINFILE
	       An error occurred while trying to read a LINTERP table from disk.

       GD_E_RECURSE_LEVEL
	       Too  many levels of recursion were encountered while trying to resolve field_code.  This usually indicates a circular dependency in
	       field specification in the dirfile.

       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_open(3), gd_getdata(3), gd_error(3), gd_error_string(3)

Version 0.7.0							  3 November 2010						 gd_native_type(3)