I am converting some code from SCO unix to Linux. the SCO code increments a structure with ((STRUCT_DEF *)variable)++;

gcc on Linux gives a lvalue error. I am assuming and would like confirmation if possible, that the replacement for linux would be.
variable = (STRUCT_DEF *)(variable + sizeof(STRUCT_DEF));
is this correct?

And then there is this:

SCO code: (STRUCT_DEF *) variable +=3;
is this adding 3 or 3 X size of sturcture?

Linux replacement would be?
variable = ((STRUCT_DEF *)variable)+3;
or
variable = (STRUCT_DEF *)(variable + (sizeof(STRUCT_DEF) * 3);

Thanks for any help.

Scott Hawley
scott@shawley.net

Not if variable isn't a char pointer.
If it's adding 3 bytes that is really bad code, so I would assume 3 X size of structure.


The second variation has the same problem that I mentioned above (i.e. that it would add 3*sizeof(STRUCT_DEF)*sizeof(*variable) bytes).

I wouldn't put my email on a public web page if I were you.

Thanks for the response and advice!