Address syntax

From: Adam Warner (usenet_at_consulting.net.nz)
Date: 12/29/04 

Date: Thu, 30 Dec 2004 00:48:35 +1300

Hi all,

In the code snippet below I successfully determine the address of val1:*

   struct o val1=l_SYM_2B(&a).o[0];
   print_aesthetic(&val1);

The structure o is heavyweight. I understand (hopefully correctly) that
(barring compiler optimisations) C will shallow copy the structure into
val1.

As I merely wished to pass the structure to print_aesthetic I combined the
statements to avoid creating an intermediate copy of the structure. This
was my attempt:

   print_aesthetic(&(l_SYM_2B(&a).o[0]));

I discovered that the only way to get GCC 3.4 to accept this syntax was to
append the -std=c99 compiler option. Otherwise GCC produced the error
message "invalid operands to binary +", i.e. it appeared to be trying to
interpret the address operator as a binary AND.

Is this a bug in GCC's pre-C99 support or has the syntax of C been changed
in C99 to support the code I wrote above? If so, thank goodness!

Regards,
Adam

* Footnote:
a is a local variable of type struct o.
l_SYM_2B(struct o * arg0) returns struct v1, defined as { struct o o[1]; };
print_aesthetic has the prototype struct v1 print_aesthetic(struct o *);