Re: Change in preprocessor behavior

[Mike Stump <mstump@apple.com>]

On Monday, December 30, 2002, at 02:38 PM, Stephen Lindholm wrote:
> The stringize and token-pasting operators seem to no longer work in the
> "cpp" phases of compilation, but they worked in "cpp" in early  
> versions of
> gcc (2.95.3). I can't find it written that those operations must occur  
> in
> phases 1-4, but # and ## are "preprocessing-op-or-punc" and it would  
> seem
> that they should therefore be processed in phase 4.
>
> Am I doing something wrong?
>
>
> Using this example from the cpp info page:
>
> #define COMMAND(NAME)  { #NAME, NAME ## _command }
>
> struct command commands[] =
> {
>   COMMAND (quit),
>   COMMAND (help),
> };
>
> I get this as expected on an old version of cpp (2.95.3):
>
> Xenon > cpp test2
> # 1 "test2"
>
>
> struct command commands[] =
> {
>   { "quit",  quit_command } ,
>   { "help",  help_command } ,
> };
>
> and this on a new version of cpp (3.1):
>
> thrush:~% cpp test2
> # 1 "test2"
>
>
> struct command commands[] =
> {
>   { #quit, quit ## _command },
>   { #help, help ## _command },
> };

My experience differs from yours:

bash-2.05a$ cat b.cc
#define COMMAND(NAME)  { #NAME, NAME ## _command }

struct command commands[] =
{
   COMMAND (quit),
   COMMAND (help),
};
bash-2.05a$ gcc -v -E b.cc
Reading specs from /usr/libexec/gcc/darwin/ppc/3.1/specs
Thread model: posix
Apple Computer, Inc. GCC version 1175, based on gcc version 3.1  
20020420 (prerelease)
  /usr/libexec/gcc/darwin/ppc/3.1/cpp0 -lang-c++ -D__GNUG__=3  
-D__DEPRECATED -D__EXCEPTIONS -D__GXX_ABI_VERSION=100 -v -D__GNUC__=3  
-D__GNUC_MINOR__=1 -D__GNUC_PATCHLEVEL__=0 -D__APPLE_CC__=1175  
-D__ppc__ -D__POWERPC__ -D__NATURAL_ALIGNMENT__ -D__MACH__  
-D__BIG_ENDIAN__ -D__APPLE__ -D__ppc__ -D__POWERPC__  
-D__NATURAL_ALIGNMENT__ -D__MACH__ -D__BIG_ENDIAN__ -D__APPLE__  
-D__NO_INLINE__ -D__STDC_HOSTED__=1 -D__DYNAMIC__ b.cc
GNU CPP version 3.1 20020420 (prerelease) (cpplib) (Darwin/PowerPC)
ignoring nonexistent directory "/usr/local/include"
ignoring nonexistent directory  
"/usr/lib/gcc-lib/ppc-darwin/3.1/../../../../ppc-darwin/include"
ignoring nonexistent directory "/Local/Library/Frameworks"
#include "..." search starts here:
#include <...> search starts here:
  /usr/include/gcc/darwin/3.1/g++-v3
  /usr/include/gcc/darwin/3.1/g++-v3/ppc-darwin
  /usr/include/gcc/darwin/3.1/g++-v3/backward
  /usr/include/gcc/darwin/3.1
  /usr/include
End of search list.
Framework search starts here:
  /System/Library/Frameworks
  /Library/Frameworks
End of framework search list.
# 1 "b.cc"
# 1 "<built-in>"
# 1 "<command line>"
# 1 "b.cc"


struct command commands[] =
{
   { "quit", quit_command },
   { "help", help_command },
};

and

bash-2.05a$ cpp -v b.cc
Reading specs from /usr/libexec/gcc/darwin/ppc/3.1/specs
Thread model: posix
Apple Computer, Inc. GCC version 1175, based on gcc version 3.1  
20020420 (prerelease)
  /usr/libexec/gcc/darwin/ppc/3.1/cpp0 -lang-c++ -D__DEPRECATED  
-D__EXCEPTIONS -D__GXX_ABI_VERSION=100 -v -$ -iprefix  
/usr/libexec/gcc/darwin/ppc/default/../libexec/gcc/darwin/ppc/3.1/  
-D__ppc__ -D__POWERPC__ -D__NATURAL_ALIGNMENT__ -D__MACH__  
-D__BIG_ENDIAN__ -D__APPLE__ -D__ppc__ -D__POWERPC__  
-D__NATURAL_ALIGNMENT__ -D__MACH__ -D__BIG_ENDIAN__ -D__APPLE__  
-D__NO_INLINE__ -D__STDC_HOSTED__=1 -D__DYNAMIC__ -D__GNUC__ b.cc
GNU CPP version 3.1 20020420 (prerelease) (cpplib) (Darwin/PowerPC)
ignoring nonexistent directory  
"/usr/libexec/gcc/darwin/ppc/default/../libexec/gcc/darwin/ppc/3.1/+-v3"
ignoring nonexistent directory  
"/usr/libexec/gcc/darwin/ppc/default/../libexec/gcc/darwin/ppc/3.1/+- 
v3/ppc-darwin"
ignoring nonexistent directory  
"/usr/libexec/gcc/darwin/ppc/default/../libexec/gcc/darwin/ppc/3.1/+- 
v3/backward"
ignoring nonexistent directory  
"/usr/libexec/gcc/darwin/ppc/default/../libexec/gcc/darwin/ppc/3.1/+- 
v3/.."
ignoring nonexistent directory "/usr/local/include"
ignoring nonexistent directory  
"/usr/lib/gcc-lib/ppc-darwin/3.1/../../../../ppc-darwin/include"
ignoring nonexistent directory "/Local/Library/Frameworks"
#include "..." search starts here:
#include <...> search starts here:
  /usr/include/gcc/darwin/3.1/g++-v3
  /usr/include/gcc/darwin/3.1/g++-v3/ppc-darwin
  /usr/include/gcc/darwin/3.1/g++-v3/backward
  /usr/include/gcc/darwin/3.1
  /usr/include
End of search list.
Framework search starts here:
  /System/Library/Frameworks
  /Library/Frameworks
End of framework search list.
# 1 "b.cc"
# 1 "<built-in>"
# 1 "<command line>"
# 1 "b.cc"


struct command commands[] =
{
   { "quit", quit_command },
   { "help", help_command },
};

I cannot explain why.  My best guess is that you are not using 1175, or  
that you didn't use gcc_select to select gcc3.  What does gcc_select  
say when you run it?