命名全局范围的一次性标识符

有时,在使用宏生成代码时,有必要创建具有全局作用域的标识符,但这些标识符对于创建它们的直接上下文之外的任何内容都没有真正的用处。例如,假设有必要在编译时将数组或其他索引资源分配到不同大小的块中。

/* Produce an enumeration of some story-book characters, and allocate some
   arbitrary index resource to them.  Both enumeration and resource indices
   will start at zero.

   For each name, defines HPID_xxxx to be the enumeration of that name.
   Also defines HP_ID_COUNT to be the total number of names, and
   HP_TOTAL_SIZE to be the total resource requirement, and creates an
   array hp_starts[HP_ID_COUNT+1].  Each character n is allocated resources
   from hp_starts[n] through (but not including) hp_starts[n+1].
*/

/* Give the names and their respective lengths */
#define HP_LIST \
  HP_ITEM(FRED, 4) \
  HP_ITEM(GEORGE, 6) \
  HP_ITEM(HARRY, 5) \
  HP_ITEM(RON, 3) \
  HP_ITEM(HERMIONE, 8) \
  /* BLANK LINE REQUIRED TO ABSORB LAST BACKSLASH */

#define HP_ITEM(name, length) HPID_##name,
typedef enum { HP_LIST HP_ID_COUNT} HP_ID;
#undef HP_ITEM

#define HP_ITEM(name, length) ZZQ_##name}; enum {ZZQX_##name=ZZQ_##name+(length)-1,
enum { HP_LIST HP_TOTAL_SIZE};
#undef HP_ITEM

#define HP_ITEM(name, length) ZZQ_##name,
const unsigned char hp_starts[] = { HP_LIST HP_TOTAL_SIZE};
#undef HP_ITEM

#include "stdio.h"

void main(void)
{
  int i;

  printf("ID count=%d Total size=%d\n",HP_ID_COUNT,HP_TOTAL_SIZE);
  for (i=0; HP_ID_COUNT > i; i++) /* Reverse conditional to avoid lt sign */
    printf("  %2d=%3d/%3d\n", i, hp_starts[i], hp_starts[i+1]-hp_starts[i]);
  printf("IDs are: \n");
#define HP_ITEM(name, length) printf("  %2d=%s\n",HPID_##name, #name);
  HP_LIST
#undef HP_ITEMS

}

是否有任何命名此类标识符的常规约定,以尽量减少冲突的可能性,并尽量减少它们可能产生的任何混淆?在上述场景中,标识符ZZQ\u xxx将与hp\u start[HPID\u xxx]相同,并且在某些上下文中可能有用,尽管它们的主要目的是构建数组,并在计算其他ZZQ值和hp\u TOTAL\u大小时充当占位符。然而,标识符ZZQX\u xxx是无用的;它们的唯一目的是在为后续项设置枚举值时充当占位符。有什么好办法来命名这些东西吗?

顺便说一句,我为小微控制器开发的RAM是在一个更大的溢价比代码空间。代码是通过编译微软VC++来模拟的,但对于生产来说是使用交叉编译器在直C编译的;因此代码必须在C和C++中编译。

对于类似的任务,还有其他预处理器技巧可以推荐吗?