Re: error: redefinition of `struct random_data'

[Bruno Haible]

Hi Sam,

> I am getting this error 
> when compiling gllib in the regexp clisp module on mingw and cygwin:
> gcc -mno-cygwin -DHAVE_CONFIG_H -I. -I/.../current/modules/regexp/gllib -I.. 
> -I/.../top/include -I/.../current/build-mingw-g-7/gllib 
> -I/.../current/build-mingw-g-7  -g -O2 -W -Wswitch -Wcomment -Wpointer-arith 
> -Wimplicit -Wreturn-type -Wmissing-declarations -Wno-sign-compare 
> -Wno-format-nonliteral -falign-functions=4 -D_WIN32 -g -O0 -DDEBUG_OS_ERROR 
> -DDEBUG_SPVW -DDEBUG_BYTECODE -DSAFETY=3 -DENABLE_UNICODE 
> -DNO_TERMCAP_NCURSES 
> -DDYNAMIC_FFI -DDYNAMIC_MODULES -DNO_GETTEXT -I.  -DDLL_EXPORT -DPIC 
> -I/.../current/build-mingw-g-7/  -MT malloc.o -MD -MP -MF .deps/malloc.Tpo -c 
> -o malloc.o /.../current/modules/regexp/gllib/malloc.c
> In file included from /.../current/modules/regexp/gllib/malloc.c:
> 32:./stdlib.h:65: error: redefinition of `struct random_data'
> make[4]: *** [malloc.o] Error 1
> 
> indeed, I have stdlib.h both in gllib and regexp/gllib.

It sounds like you have two invocations for gnulib-tool, one for gllib,
and one for regexp/gllib. During the configurations, it was determined that
the system's <stdlib.h> does not define 'struct random_data', so it is
gnulib's task to define it. So both generated stdlib.h files now define
'struct random_data'. Now, in your compilation the -I options refer to
both directories where they exist, hence the #include_next statements
chain the two files. You probably renamed the inclusion guard (_GL_STDLIB_H)
appropriate (as recommended). And now the two structure definitions clash.

There are two ways out:
  a) gnulib should add another guard so as to ensure that 'struct random_data'
     does not get defined twice.
  b) You use the gnulib-tool option --avoid-stdlib in regexp/gllib.

I think the problem you encountered is not specific to clisp, therefore I'm
applying approach a).


2010-10-11  Bruno Haible  <address@hidden>

        stdlib: Allow multiple gnulib generated replacements to coexist.
        * lib/stdlib.in.h (struct random_data): Avoid identical redefinition.
        Reported by Sam Steingold <address@hidden>.

--- a/lib/stdlib.in.h
+++ b/lib/stdlib.in.h
@@ -61,6 +61,9 @@
 #endif
 
 #if address@hidden@
+/* Define 'struct random_data'.
+   But allow multiple gnulib generated <stdlib.h> replacements to coexist.  */
+# if !GNULIB_defined_struct_random_data
 struct random_data
 {
   int32_t *fptr;                /* Front pointer.  */
@@ -71,6 +74,8 @@ struct random_data
   int rand_sep;                 /* Distance between front and rear.  */
   int32_t *end_ptr;             /* Pointer behind state table.  */
 };
+#  define GNULIB_defined_struct_random_data 1
+# endif
 #endif
 
 #if (@GNULIB_MKSTEMP@ || @GNULIB_GETSUBOPT@ || defined GNULIB_POSIXCHECK) && ! 
defined __GLIBC__ && !((defined _WIN32 || defined __WIN32__) && ! defined 
__CYGWIN__)