自学教程：C++ Data_Make_Struct函数代码示例

static VALUErb_hps_alloc(VALUE klass){  hashpipe_status_t * p;  VALUE v;    v = Data_Make_Struct(klass, hashpipe_status_t, 0, free, p);  memset(p, 0, sizeof(hashpipe_status_t));  return v;}

static VALUE allocate(VALUE klass) {    VALUE obj;    mysql_client_wrapper * wrapper;    obj = Data_Make_Struct(klass, mysql_client_wrapper, rb_mysql_client_mark, rb_mysql_client_free, wrapper);    wrapper->encoding = Qnil;    wrapper->active = 0;    wrapper->closed = 1;    wrapper->client = (MYSQL*)malloc(sizeof(MYSQL));    return obj;}

static VALUEmemptr_allocate(VALUE klass){    Pointer* p;    VALUE obj = Data_Make_Struct(klass, Pointer, NULL, memptr_release, p);    p->rbParent = Qnil;    p->memory.flags = MEM_RD | MEM_WR;    return obj;}

static VALUE rb_gsl_sf_coulomb_wave_FG_e(VALUE obj, VALUE eta, VALUE x,					 VALUE L_F, VALUE k){  gsl_sf_result *F, *Fp, *G, *Gp;  VALUE vF, vFp, vG, vGp;  double exp_G, exp_F;  int status;  Need_Float(eta); Need_Float(x); Need_Float(L_F);  CHECK_FIXNUM(k);  vF = Data_Make_Struct(cgsl_sf_result, gsl_sf_result, 0, free, F);  vFp = Data_Make_Struct(cgsl_sf_result, gsl_sf_result, 0, free, Fp);  vG = Data_Make_Struct(cgsl_sf_result, gsl_sf_result, 0, free, G);  vGp = Data_Make_Struct(cgsl_sf_result, gsl_sf_result, 0, free, Gp);  status = gsl_sf_coulomb_wave_FG_e(NUM2DBL(eta), NUM2DBL(x), NUM2DBL(L_F),				    FIX2INT(k), F, Fp, G, Gp, &exp_F, &exp_G);  return rb_ary_new3(7, vF, vFp, vG, vGp,		     rb_float_new(exp_F), rb_float_new(exp_G), INT2FIX(status));}

static VALUE rb_gsl_sf_multiply_e(VALUE obj, VALUE x, VALUE y){  gsl_sf_result *r;  VALUE v;  int status;  Need_Float(x); Need_Float(y);  v = Data_Make_Struct(cgsl_sf_result, gsl_sf_result, 0, free, r);  status = gsl_sf_multiply_e(NUM2DBL(x), NUM2DBL(y), r);  return v;}

static VALUE rb_gsl_sf_lnchoose_e(VALUE obj, VALUE n, VALUE m){  gsl_sf_result *rslt = NULL;  VALUE v;  int status;  CHECK_FIXNUM(n); CHECK_FIXNUM(m);  v = Data_Make_Struct(cgsl_sf_result, gsl_sf_result, 0, free, rslt);  status = gsl_sf_lnchoose_e(FIX2INT(n), FIX2INT(m), rslt);  return v;}

static VALUEsymbol_allocate(VALUE klass){    LibrarySymbol* sym;    VALUE obj = Data_Make_Struct(klass, LibrarySymbol, NULL, -1, sym);    sym->name = Qnil;    sym->library = Qnil;    sym->base.rbParent = Qnil;    return obj;}

VALUErb_ldap_entry_new (LDAP * ldap, LDAPMessage * msg){  VALUE val;  RB_LDAPENTRY_DATA *edata;  val = Data_Make_Struct (rb_cLDAP_Entry, RB_LDAPENTRY_DATA,			  0, rb_ldap_entry_free, edata);  edata->ldap = ldap;  edata->msg = msg;  return val;}

static VALUErb_ds_artist_alloc (VALUE klass){	rb_ds_artist *artist;	VALUE obj;	obj = Data_Make_Struct(klass, rb_ds_artist,	                       NULL, NULL, artist);	return obj;}

static VALUErb_ds_playlist_alloc (VALUE klass){	rb_ds_playlist *pls;	VALUE obj;	obj = Data_Make_Struct(klass, rb_ds_playlist, NULL,	                       rb_ds_playlist_free, pls);	return obj;}

static VALUEtype_allocate(VALUE klass){    Type* type;    VALUE obj = Data_Make_Struct(klass, Type, NULL, -1, type);    type->nativeType = -1;    type->ffiType = &ffi_type_void;        return obj;}

static VALUE num_alloc(VALUE klass) {  decNumber self_struct, *self_ptr;  decContext context;  VALUE self;  self_ptr = &self_struct;  self = Data_Make_Struct(klass, decNumber, 0, free, self_ptr);  decContextDefault(&context, DEC_INIT_BASE);  (*self_ptr).bits = DECNAN;  return self;}

static VALUE rb_gsl_sf_pow_int_e(VALUE obj, VALUE x, VALUE n){  gsl_sf_result *rslt = NULL;  VALUE v;  int status;  Need_Float(x);  CHECK_FIXNUM(n);  v = Data_Make_Struct(cgsl_sf_result, gsl_sf_result, 0, free, rslt);  status = gsl_sf_pow_int_e(NUM2DBL(x), FIX2INT(n), rslt);  return v;}

static VALUE rb_gsl_sf_lngamma_sgn_e(VALUE obj, VALUE x){  gsl_sf_result *rslt = NULL;  VALUE v;  int status;  double sgn;  Need_Float(x);  v = Data_Make_Struct(cgsl_sf_result, gsl_sf_result, 0, free, rslt);  status = gsl_sf_lngamma_sgn_e(NUM2DBL(x), rslt, &sgn);  return rb_ary_new3(2, v, rb_float_new(sgn));}

static VALUE static_gedcom_date_new( int    argc,                                     VALUE *argv,                                     VALUE  klass ){  char *s_date;  int   i_type;  int   rc;  VALUE date;  VALUE type;  VALUE new_date;  gedDATEVALUE_t parsed_date;  gedDATEVALUE_t *temp;  if( rb_scan_args( argc, argv, "11", &date, &type ) == 1 )  {    i_type = gctDEFAULT;  }  else  {    i_type = FIX2INT( type );  }      s_date = STR2CSTR( date );  rc = parseGEDCOMDate( s_date, &parsed_date, i_type );  if( rc != 0 )  {    VALUE err_msg;    err_msg = rb_str_new2( "format error at '" );    if( parsed_date.date1.flags & gfNONSTANDARD )      rb_str_cat( err_msg, parsed_date.date1.data.phrase, strlen( parsed_date.date1.data.phrase ) );    else      rb_str_cat( err_msg, parsed_date.date2.data.phrase, strlen( parsed_date.date2.data.phrase ) );    rb_str_cat( err_msg, "'", 1 );    if( rb_block_given_p() )    {      rb_yield( err_msg );    }    else    {      rb_raise( eDateFormatException, STR2CSTR( err_msg ) );    }  }  new_date = Data_Make_Struct( klass, gedDATEVALUE_t, 0, 0, temp );  memcpy( temp, &parsed_date, sizeof( parsed_date ) );  return new_date;}

static rb_context_t *cont_new(VALUE klass){    rb_context_t *cont;    volatile VALUE contval;    contval = Data_Make_Struct(klass, rb_context_t, cont_mark, cont_free, cont);    cont->self = contval;    cont_init(cont);    return cont;}

static VALUErb_ds_session_alloc (VALUE klass){	rb_ds_session *session;	VALUE obj;	obj = Data_Make_Struct(klass, rb_ds_session, NULL,	                       rb_ds_session_free, session);	return obj;}

static VALUE rb_gsl_sf_lnchoose_e(VALUE obj, VALUE n, VALUE m){  gsl_sf_result *rslt = NULL;  VALUE v;  // local variable "status" declared and set, but never used  //int status;  CHECK_FIXNUM(n); CHECK_FIXNUM(m);  v = Data_Make_Struct(cgsl_sf_result, gsl_sf_result, 0, free, rslt);  /*status =*/ gsl_sf_lnchoose_e(FIX2INT(n), FIX2INT(m), rslt);  return v;}

static VALUE solver_alloc(VALUE klass){    csolver *cslv;    VALUE rslv;    rslv = Data_Make_Struct(klass, csolver, NULL, solver_free, cslv);    cslv->solver = wrap_solver_new();    cslv->result = NOT_SOLVED_YET;    return rslv;}

static VALUEsbr_allocate(VALUE klass){    StructByReference* sbr;    VALUE obj = Data_Make_Struct(klass, StructByReference, sbr_mark, -1, sbr);    sbr->rbStructClass = Qnil;    return obj;}

static ThreadData*thread_data_init(void){    ThreadData* td;    VALUE obj;    obj = Data_Make_Struct(rb_cObject, ThreadData, NULL, -1, td);    rb_thread_local_aset(rb_thread_current(), id_thread_data, obj);    return td;}

static VALUEmemory_allocate(VALUE klass){    AbstractMemory* memory;    VALUE obj;    obj = Data_Make_Struct(klass, AbstractMemory, NULL, -1, memory);    memory->ops = &rbffi_AbstractMemoryOps;    memory->access = MEM_RD | MEM_WR;    return obj;}

static VALUEpg_typemap_s_allocate( VALUE klass ){	VALUE self;	t_typemap *this;	self = Data_Make_Struct( klass, t_typemap, NULL, -1, this );	this->funcs = pg_typemap_funcs;	return self;}

static VALUE allocate(VALUE klass) {  VALUE obj;  tinytds_client_wrapper *cwrap;  obj = Data_Make_Struct(klass, tinytds_client_wrapper, rb_tinytds_client_mark, rb_tinytds_client_free, cwrap);  cwrap->closed = 1;  cwrap->charset = Qnil;  cwrap->userdata = malloc(sizeof(tinytds_client_userdata));  cwrap->userdata->closed = 1;  rb_tinytds_client_reset_userdata(cwrap->userdata);  return obj;}

static VALUEstruct_allocate(VALUE klass){    Struct* s;    VALUE obj = Data_Make_Struct(klass, Struct, struct_mark, struct_free, s);        s->rbPointer = Qnil;    s->rbLayout = Qnil;    return obj;}

static VALUEstruct_field_allocate(VALUE klass){    StructField* field;    VALUE obj;    obj = Data_Make_Struct(klass, StructField, struct_field_mark, -1, field);    field->rbType = Qnil;    field->rbName = Qnil;    return obj;}

static VALUE allocate(VALUE klass){  MYSQL * client;  return Data_Make_Struct(      klass,      MYSQL,      NULL,      rb_mysql_client_free,      client  );}

static VALUEpg_composite_decoder_allocate( VALUE klass ){	t_pg_composite_coder *this;	VALUE self = Data_Make_Struct( klass, t_pg_composite_coder, NULL, -1, this );	pg_coder_init_decoder( self );	this->elem = NULL;	this->needs_quotation = 1;	this->delimiter = ',';	rb_iv_set( self, "@elements_type", Qnil );	return self;}

static VALUEinline_array_allocate(VALUE klass){    InlineArray* array;    VALUE obj;    obj = Data_Make_Struct(klass, InlineArray, inline_array_mark, -1, array);    array->rbField = Qnil;    array->rbMemory = Qnil;    return obj;}