templates, htonl (volatile) problem

[Andrej Filipcic]

Hi,

There is a strange behaviour with htonl function , templates and egcs-1.1.2 on
glibc-2.1.1 PII system (RH6.0).

The following program
-----------------
#include <cstdio>
#include <netinet/in.h>

template <class T>
class A 
{
 public:
  A() {};
  ~A() {};
  unsigned int testf() {
    return htonl( 0x01020304 ); 
  } 
};

int main() { 
  A<int> a;
  printf("%d\n",a.testf());
}
------------------
compiles with no optimization. If g++ -O is invoked, the following message 
appears:
0.cc: In method `unsigned int A<int>::testf<int>()':
0.cc:17:   instantiated from here
0.cc:11: `volatile' undeclared (first use this function)
0.cc:11: (Each undeclared identifier is reported only once
0.cc:11: for each function it appears in.)
0.cc:11: warning:  qualifier ignored on asm

When using -O, htonl is substituted with the following macro (g++ -E -O)
  unsigned int testf() {
    return (__extension__	({ register unsigned int __v;	
    if (__builtin_constant_p (   0x01020304   ))	
    __v = ((((    0x01020304    ) & 0xff000000) >> 24) | 
    (((    0x01020304    ) & 0x00ff0000) >>  8) |	(((    0x01020304    )
     & 0x0000ff00) <<  8) | (((    0x01020304    ) & 0x000000ff) << 24)) ;  
     	else	
__asm__ __volatile__ ("rorw $8, %w0;"	"rorl $16, %0;"	"rorw $8, %w0"	
	: "=r" (__v)	: "0" ((unsigned int) (   0x01020304   ))	
	: "cc");	__v; }))  ; 
  }

The same code with the same macro compiles without problems, 
if templates are skipped. The same happens with 19990615 snapshot.

Thanks for your time

Andrej

_____________________________________________________________
   Andrej Filipcic,        E-mail: Andrej.Filipcic@ijs.si
   Department of Experimental High Energy Physics - F9
   Jozef Stefan Institute, Jamova 39, P.o.Box 3000
   SI-1001 Ljubljana, Slovenia
   Tel.: +386-61-177-3674    Fax: +386-61-125-7074
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