UF_CGM_export_error_f_t

An export_error callback of type UF_CGM_export_error_f_t is invoked if
some error occurs while generating the CGM file. In this callback,
the application can restore the state of application objects/geometry
and can free resources allocated for the operation.

The export_error callback is invoked only if the pre_export callback
returned TRUE for the same export operation.

If the export_error callback is invoked, then the post_export callback
is not invoked for the same export operation.

UF_CGM_post_export_f_t

A post_export callback of type UF_CGM_post_export_f_t is invoked after
geometry is successfully recorded in a CGM file. In this callback,
the application can restore the state of application objects/geometry
and can free resources allocated for the operation.

The post_export callback is invoked only if the pre_export callback
returned TRUE for the same export operation.

The post_export callback is not invoked if an error occurs during the
export operation. The export_error callback is invoked instead.

UF_CGM_pre_export_f_t

A pre_export callback of type UF_CGM_pre_export_f_t is invoked before
geometry is recorded in a CGM file during a CGM export operation.
In this function, the application might enable or disable display
of application objects, as appropriate.

If the application decides to take some action in response to the
export operation, then the application can return a (void ) pointer
to arbitrary application data in the appl_data parameter. This pointer
will later be passed as the appl_data parameter to the post_export
and export_error callback functions.

The application returns TRUE from the pre_export callback if the
operation is of interest, and FALSE otherwise. The post_export and
export_error callback functions are not invoked unless the pre_export
callback returns TRUE.