对于一个直接在UG中新建的拉伸特征，到底怎样才能获得其参数？

为什么我写的代码，对UF_MODL_create_extruded创建的特征有效，对直接在UG中新建的拉伸特征无效？
我遍历了部件中的每一个对象，对每一个对象都调用了UF_MODL_ask_extrusion，可见不是TAG传递错误的问题，那为什么还是无效？
难道UF_MODL_ask_extrusion只对UF_MODL_create_extruded创建的特征有效麽？
下面是我写的代码：
#include <uf.h>
#include <uf_exit.h>
#include <uf_ui.h>
#include <uf_part.h>
#include <uf_obj.h>
#include <uf_modl.h>
#include <stdlib.h>
#include <stdio.h>
#include <uf_curve.h>
#include <math.h>
#include <string.h>
#include <uf_csys.h>
#include <uf_mtx.h>



#if ! defined ( __hp9000s800 ) && ! defined ( __sgi ) && ! defined ( __sun )
# include <strstream>
#   include <iostream>
using std:strstream;
using std::endl;
using std::ends;
using std::cerr;
#else
# include <strstream.h>
#   include <iostream.h>
#endif
#include "UF_MODL_ask_extrusion_EX.h"


tag_t create_line(double start_x,double start_y,double start_z,double end_x,double end_y,double end_z)
{
UF_CURVE_line_t line_coords;
UF_CURVE_line_p_t p_line_coords=&line_coords;
line_coords.start_point[0]=start_x;
line_coords.start_point[1]=start_y;
line_coords.start_point[2]=start_z;
line_coords.end_point[0]=end_x;
line_coords.end_point[1]=end_y;
line_coords.end_point[2]=end_z;
tag_t line_tag=NULL_TAG;
UF_CURVE_create_line(p_line_coords,&line_tag);
return(line_tag);
}



void object_cycle_all()
{
logical region_specified=true;
logical solid_creation=true;
   
int n_objects=3;//被拉伸的曲线的条数
   
tag_t objects[3];//指向一个包含被拉伸的曲线的ID的数组
objects[0]=create_line(0,0,0,1,2,3);
objects[1]=create_line(1,2,3,4,5,6);
objects[2]=create_line(4,5,6,0,0,0);
tag_t* p_object=objects;
   
double direction[3]={0.0,0.0,0.0};//拉伸的方向向量
double region_point[3]={0.0,0.0,0.0};
   
char* taper_angle="0.0";//拉伸后沿轴的倾斜角度
char* limits[2]={"0","0"};//拉伸的幅度上下限
char* offsets[2]={"0.0","0.0"};
   
UF_MODL_SWEEP_TRIM_object_t trim_ptr;
tag_t trim[3]={NULL_TAG,NULL_TAG,NULL_TAG};
trim_ptr.trim_objects=trim;
trim_ptr.trim_count=3;
trim_ptr.sign=UF_MODL_SWEEP_TRIM_NONE;
trim_ptr.thru_bodies=NULL;
trim_ptr.num_thru_bodies=0;
UF_MODL_SWEEP_TRIM_object_p_t p_trim_ptr;
    int error=0;

//－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－
int i=0;
tag_t display_part_tag=UF_PART_ask_display_part();  
tag_t object_tag=NULL_TAG;
int num=0;
char* feature_type="";
FILE* fp=fopen("D:\\对象的编号.txt","w");
do
{
  object_tag=UF_OBJ_cycle_all(display_part_tag,object_tag);
  //i=ask_extruded(object_tag);

  num++;
  UF_MODL_ask_feat_name(object_tag,&feature_type);
  error=UF_MODL_ask_extrusion(object_tag, &n_objects, &p_object,
        &p_trim_ptr, &taper_angle, limits, offsets, region_point,
        &reg;ion_specified, &solid_creation, direction);
  fprintf(fp,"\n对象%d的id为：%u,其类型为：%s\n错误号为：%d\n",
   num,object_tag,feature_type,error);
                       
  
}while(object_tag!=NULL_TAG);
fclose(fp);
}



extern "C" DllExport void ufusr( char *parm, int *returnCode, int rlen )
{
    /* Initialize the API environment */
    int errorCode = UF_initialize();
    if ( 0 == errorCode )
    {
  object_cycle_all();
        /* TODO: Add your application code here */
        /* Terminate the API environment */
        errorCode = UF_terminate();
    }
    /* Print out any error messages */
    PrintErrorMessage( errorCode );
}


extern "C" int ufusr_ask_unload( void )
{
    return( UF_UNLOAD_IMMEDIATELY );
}
/* PrintErrorMessage
**
**     Prints error messages to standard error and the Unigraphics status
**     line. */
static void PrintErrorMessage( int errorCode )
{
    if ( 0 != errorCode )
    {
        /* Retrieve the associated error message */
        char message[133];
        UF_get_fail_message( errorCode, message );
        /* Print out the message */
        UF_UI_set_status( message );
        // Construct a buffer to hold the text.
        ostrstream error_message;
        // Initialize the buffer with the required text.
        error_message << endl
                      << "Error:" << endl
                      << message
                      << endl << endl << ends;
     // Write the message to standard error
        cerr << error_message.str();
    }
}
打印错误号error的值总是非0，一般是580001和875004。

编译、链接、调用DLL都没有错
就是完成不了功能

走过路过的回个话啊