Yes, pointer arithmetic is scaled by the item size. Works kind of like a
subscript. If foo is an int* then foo+1 points to the next integer. (IOW
foo+4 if you think in assembler terms.)
The basic strategy is to cast it to a char* and then back.
If you would like, here are two template functions that will do the trick
you want to accomplish.
// Pointer absolute arithmetic
// This one matches if no explicit typename
template<typename T> static inline T *PointerAdd(const T *ptr, const int
increment)
{
return (T *)( reinterpret_cast<const char *>(ptr)+increment );
}
// This one matches if explicit typename
template<typename T> static inline T *PointerAdd(const void *ptr, const
int increment)
{
return (T *)( reinterpret_cast<const char *>(ptr)+increment );
}
How to use? Here is an example of adding an absolute length to a struct
pointer:
apfePtr = PointerAdd(apfePtr, apfePtr->apfelen);
Charles
-----Original Message-----
From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On
Behalf Of Seymour J Metz
Sent: Thursday, February 8, 2018 8:12 AM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: Re: Silly C problem adding hex 6C
Isn't pointer arithmetic in C scaled by the item size?
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