Question

我试图在c。

中初始化一个新结构

我的语法有什么问题？

    AddressItem_Callback_ContextType *context;

   //check if icons need to be downloaded
   if (pEntity->cBigIcon[0] != 0){
      if (res_get(RES_BITMAP,RES_SKIN, pEntity->cBigIcon) == NULL){

          context = {pEntity->iID, pEntity->cBigIcon};
          //context->Icon = pEntity->cBigIcon;
          //context->iID = pEntity->iID;

         res_download(RES_DOWNLOAD_IMAGE, pEntity->cBigIcon, NULL, "",TRUE, 1, addressItem_icon_download_callback, context );
      }
   }

我也遇到了语法错误：

    AddressItem_Callback_ContextType *context = {0,NULL};

   //check if icons need to be downloaded
   if (pEntity->cBigIcon[0] != 0){
      if (res_get(RES_BITMAP,RES_SKIN, pEntity->cBigIcon) == NULL){

          //context = {pEntity->iID, pEntity->cBigIcon};
          context->Icon = pEntity->cBigIcon;
          context->iID = pEntity->iID;

         res_download(RES_DOWNLOAD_IMAGE, pEntity->cBigIcon, NULL, "",TRUE, 1, addressItem_icon_download_callback, context );
      }
   }

   if (pEntity->cSmallIcon[0] != 0){
      if (res_get(RES_BITMAP,RES_SKIN, pEntity->cSmallIcon) == NULL){

          //context = {pEntity->iID, pEntity->cSmallIcon};
          context->Icon = pEntity->cSmallIcon;
          context->iID = pEntity->iID;

         res_download(RES_DOWNLOAD_IMAGE, pEntity->cSmallIcon, NULL, "",TRUE, 1, addressItem_icon_download_callback, context );
      }
   }

那么这（3）应该有效吗？

 AddressItem_Callback_ContextType context = {0,NULL};

   //check if icons need to be downloaded
   if (pEntity->cBigIcon[0] != 0){
      if (res_get(RES_BITMAP,RES_SKIN, pEntity->cBigIcon) == NULL){

          //context = {pEntity->iID, pEntity->cBigIcon};
          context.Icon = pEntity->cBigIcon;
          context.iID = pEntity->iID;

         res_download(RES_DOWNLOAD_IMAGE, pEntity->cBigIcon, NULL, "",TRUE, 1, addressItem_icon_download_callback, context );
      }
   }

   if (pEntity->cSmallIcon[0] != 0){
      if (res_get(RES_BITMAP,RES_SKIN, pEntity->cSmallIcon) == NULL){

          //context = {pEntity->iID, pEntity->cSmallIcon};
          context.Icon = pEntity->cSmallIcon;
          context.iID = pEntity->iID;

         res_download(RES_DOWNLOAD_IMAGE, pEntity->cSmallIcon, NULL, "",TRUE, 1, addressItem_icon_download_callback, context );
      }
   }

Answer 1

context = {pEntity->iID, pEntity->cBigIcon};

{}初始化列表只能在声明时使用，不能在赋值表达式中使用。

你必须在两个赋值语句中将其分解（为此你还必须初始化未初始化的context指针）。

Answer 2

正如ouah所说，初始化者必须在申报时使用，但在C99中你可以使用复合文字：

#include <stdio.h>

struct st {
    int a, b;
};

int main(void)
{
    struct st *t;

    t = &(struct st){1, 2};
    printf("%d %d\n", t->a, t->b);
    return 0;
}

在你的情况下

context = &(struct AddressItem_Callback_ContextType){pEntity->iID, pEntity->cBigIcon};

在c中初始化一个新结构

2 个答案: