Re: [lwip-users] Print Macros

[Roger Cover]

Greetings List,

 

My compiler does not substitute macros inside quotes. The proposed change would not work for me at all, since the example in the original message would result in a final string of "tcp_bind: bind to port %U16_F\n".

Regards,
Roger

---

From: 
address@hidden 
[mailto:address@hidden On Behalf Of 
Robert
Sent: Wednesday, April 13, 2011 3:41 PM
To: 
Mailing list for lwIP users
Subject: [lwip-users] Print 
Macros

I would like to see a small change to the print format macros.  
At present these macros look like this:


/* Define (sn)printf 
formatters for these lwIP types */
#define X8_F  "02x"
#define U16_F 
"hu"
#define S16_F "hd"
#define X16_F "hx"
#define U32_F "u"
#define 
S32_F "d"
#define X32_F "x"

And here is a typical invocation of one of 
these macros:

LWIP_DEBUGF(TCP_DEBUG, ("tcp_bind: bind to port 
%"U16_F"\n", port));

So after substitution, the result is 
this:

LWIP_DEBUGF(TCP_DEBUG, ("tcp_bind: bind to port %""hu""\n", 
port));

Or more readable like this:

LWIP_DEBUGF(TCP_DEBUG, 
("tcp_bind: bind to port %"   "hu"   "\n", port));  

The separate strings get combined, resulting in 
this:

LWIP_DEBUGF(TCP_DEBUG, ("tcp_bind: bind to port %hu\n", 
port));  

It's a rather clever use of macros, which unfortunately my 
compiler cannot cope with.  My compiler apparently scans the strings after 
macro insertion but before combining the strings, and it cannot cope with the 
"%" being separated from the specifier.  I propose the 
following:


Macros would be changed to this  (IE the surrounding 
quotes are left off):

#define X8_F  02x   
#define 
U16_F u     
#define S16_F d     
#define X16_F X     
#define U32_F 
lu    
#define S32_F ld    
#define X32_F 
lX    

The macro invocation would look like this  (IE 
the surrounding quotes are left off)::

LWIP_DEBUGF(TCP_DEBUG, ("tcp_bind: 
bind to port %U16_F\n", port));

This should work on all compilers, I 
believe, and the resulting code would, of course be the same.

I may have 
the only compiler that cannot cope with the macros as they are, but its been a 
pain each time I upgrade to the latest version.  If this change does not 
cause anyone else problems.

Comments?  Objections?


Best 
Regards,
Robert Laughlin