Incrementing and Decrementing Pointers

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Use the following tips:

• Point to lead bytes, not trail bytes. It is usually unsafe to have a pointer to a trail byte. It’s usually safer to scan a string forward rather than in reverse.

• There are pointer increment/decrement functions and macros available that move over a whole character:

  sz1++;
  

  becomes

  sz1 = _mbsinc( sz1 );
  

  The _mbsinc and _mbsdec functions correctly increment and decrement in character units, regardless of the character size.

• For decrements, you need a pointer to the head of the string, as in the following:

  sz2--;
  

  becomes

  sz2 = _mbsdec( sz2Head, sz2 );
  

  Alternatively, your “head” pointer could be to a valid character in the string, such that

  sz2Head < sz2
  

  You must have a pointer to a known valid lead byte.

• You may want to maintain a pointer to the previous character for faster calls to _mbsdec.

See Also   Byte Indices