From: tr.17687@z991.linuxsc.com   
      
   Keith Thompson  writes:   
      
   > David Brown  writes:   
   > [...]   
   >   
   >> How many people do you know who have actually written and use a   
   >> C11 print system using _Generic and variadic macros?  I don't know   
   >> any.  (I've written simple examples as proofs of concept, posted   
   >> in this group, but not for real use.)  It turns out that people   
   >> /don't/ have to have workarounds.  "printf" has its limitations -   
   >> there's no doubt there.  But it is good enough for most people   
   >> and most uses.   
   >   
   > I recently played around with an attempted framework using _Generic.   
   > The goal was to be able to write something like   
   >   
   >     print(s(x), s(y), s(z));   
   >   
   > where x, y, and z can be of more or less arbitrary types (integer,   
   > floating-point char*).  The problem I ran into was that only one of   
   > the generic associations is evaluated (which one is determined at   
   > compile time), but *all* of them have to be valid code.   
      
   That is annoying but it shouldn't be too hard to work around   
   it.  To verify that hypothesis I wrote this test case:   
      
      
           #include    
           #include    
           #include    
      
           #include "h/show.h"   
      
           int   
           main(){   
             unsigned long long    ull     =  -1;   
               signed long long    sll     =  -1;   
             unsigned long         ul      =  -1;   
               signed long         sl      =  -1;   
             unsigned char         uc      =  -1;   
               signed char         sc      =  -1;   
             unsigned short        us      =  -1;   
               signed short        ss      =  -1;   
             unsigned int          ui      =  -1;   
               signed int          si      =  -1;   
               char                c       =  'q';   
             float                 f       =  1.23;   
             double                d       =  3.14159265358979312;   
             double long           ld      =  6.28318530717958623;   
      
             _Bool                 yes     =  1;   
             _Bool                 no      =  !yes;   
      
             clock_t               runtime =  clock();   
             time_t                now     =  time(0);   
             off_t                 offset  =  27;   
             uint16_t              u16     =  -1;   
              int16_t              s16     =  -1;   
             uint_least32_t        uge32   =  -1;   
              int_least32_t        sge32   =  -1;   
             uint_fast32_t         uf32    =  -1;   
              int_fast32_t         sf32    =  -1;   
              char *               foo     =  "foo";   
              const char   *       bas     =  "bas";   
      
               show(   
                   uc,sc,us,ss,ui,si,ul,sl,ull,sll,   
                   c,f,d,ld,yes,no,u16,s16,uge32,sge32,   
                   runtime,now,offset,uf32,sf32,   
                   c * now / 1e8 * ld,   
                   foo, bas   
               );   
               printf( "\n" );   
      
               return  0;   
           }   
      
   which compiles under C11 and (along with the show.h include file)   
   produces output:   
      
                     uc = 255   
                     sc = -1   
                     us = 65535   
                     ss = -1   
                     ui = 4294967295   
                     si = -1   
                     ul = 18446744073709551615   
                     sl = -1   
                    ull = 18446744073709551615   
                    sll = -1   
                      c = 'q'   
                      f = 1.230000   
                      d = 3.141593   
                     ld = 6.283185   
                    yes = true   
                     no = false   
                    u16 = 65535   
                    s16 = -1   
                  uge32 = 4294967295   
                  sge32 = -1   
                runtime = 365   
                    now = 1770371790   
                 offset = 27   
                   uf32 = 18446744073709551615   
                   sf32 = -1   
     c * now / 1e8 * ld = 12569.638642   
                    foo = "foo"   
                    bas = (const char *) "bas"   
      
   --- SoupGate-Win32 v1.05   
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