standard C? -> int b = ({int a; a = 5; a;})

[John Reye]

Hello,

is it standard C... that the value obtained when evaluating a block is
the last expression in the block??

Example:
int b = ( {
int a;
a = 5;
a;
}
);



Thanks.

 

[jacob navia]

Le 14/06/12 10:23, John Reye a écrit :

Hello,

is it standard C... that the value obtained when evaluating a block is
the last expression in the block??

Example:
int b = ( {
int a;
a = 5;
a;
}
);



Thanks.

No, this is not standard c but an extension to the language provided by
the gcc compiler.

 

[James Kuyper]

Hello,

is it standard C... that the value obtained when evaluating a block is
the last expression in the block??

Example:
int b = ( {
int a;
a = 5;
a;
}
);

No. Blocks do not yield a value, and it's always a syntax error to use a
block in a context where a value would be needed. What you're describing
is an extension.

 

[gwowen]

Hello,

is it standard C... that the value obtained when evaluating a block is
the last expression in the block??

Example:
  int b = (   {
                  int a;
                  a = 5;
                  a;
                 }
             );

Thanks.

As Jacob and James have said, its a GCC extension. If you need more
information, they're called "statement expressions" or "compound
statement expressions" in the GCC manual, section 6.1.