c++ - g++ compile error on C nested struct -


i need community's compile error regarding c nested structs compiled g++.

i have following 3 files:

main.cpp (for completeness; file not required reproduce compile error):

#include <iostream> #include "ns.h"  int main( int argc, char* argv[] ) {   somefunc();   return 0; }

ns.h:

#ifndef ns_h #define ns_h  #ifdef __cplusplus extern "c" { #endif  void somefunc();  #ifdef __cplusplus } #endif  #endif // ns_h

ns.c:

#include "ns.h"  #ifdef __cplusplus extern "c" { #endif  #define my_max (42)  typedef struct _outer {   int count;   struct inner   {     int count;     void* cb;     void* ctx [ my_max ];   } inner_[ my_max ]; } outer;  outer g_outer[ 10 ];  #include "staticfuncs.h"  void somefunc() {   staticfunc(); }  #ifdef __cplusplus } #endif

staticfuncs.h:

#include <stdio.h>  #ifdef __cplusplus extern "c" { #endif  static void anotherstaticfunc() {   printf( "%s", __function__ );    struct inner* ptr = null;   ptr = &(g_outer[ 0 ].inner_[ 0 ]);   (void)ptr; }  static void staticfunc() {   printf( "%s", __function__ );   anotherstaticfunc(); }  #ifdef __cplusplus } #endif

the relevant compilation follows:

>g++ --version g++ (gcc) 4.8.3 20140911 (red hat 4.8.3-7) copyright (c) 2013 free software foundation, inc. free software; see source copying conditions.  there no warranty; not merchantability or fitness particular purpose.   >g++ -g -c ns.c -o ns.o in file included ns.c:22:0: staticfuncs.h: in function 'void anotherstaticfunc()': staticfuncs.h:12:7: error: cannot convert '_outer::inner*' 'anotherstaticfunc()::inner*' in assignment    ptr = &(g_outer[ 0 ].inner_[ 0 ]);        ^

what gives?

i'm aware in c, nested structs not referred scoping syntax, referred though not nested. i.e., i'm pretty confident in can struct inner* ptr = null; did in staticfuncs.h. more important confidence, if compile cc instead of g++, compilation goes through.

i've tried damnedest tell g++ i'm compiling c, not c++, code throwing in extern "c"s everywhere, it's still tripping on scoping of inner.

can please identify why compiler error arises , how can work around it? must use g++ compile.

the problem unchanged if staticfuncs.h staticfuncs.c instead.

the problem unchanged if static functions not static.

the problem unchanged if content of staticfuncs.h/c embedded in ns.c instead of being #includeed.

while gcc compile code c++ if has suffixes, there no way compile c g++.
difference between gcc , g++ latter compiles c++, , links c++ libraries.

the simplest fix is

struct inner {     int count;     void* cb;     void* ctx [ my_max ]; };  typedef struct _outer {   int count;   struct inner inner_[ my_max ]; } outer;

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