Compile error: template with C linkage

[maciejjan]

Hello,

while compiling the package, I get a long list of errors of the sort:

In file included from /home/janicki/projects/comphist/norma/src/gfsm/labelvector.h:21,
                 from /home/janicki/projects/comphist/norma/src/gfsm/labelvector.cpp:18:
/home/janicki/projects/comphist/norma/src/gfsmlibs.h:20:1: note: ‘extern "C"’ linkage started here
   20 | extern "C" {
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/glib-typeof.h:39,
                 from /usr/include/glib-2.0/glib/gatomic.h:28,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /home/janicki/.local/include/gfsm/gfsm.h:40,
                 from /home/janicki/projects/comphist/norma/src/gfsmlibs.h:21,
                 from /home/janicki/projects/comphist/norma/src/gfsm/labelvector.h:21,
                 from /home/janicki/projects/comphist/norma/src/gfsm/labelvector.cpp:18:
/usr/include/c++/11/type_traits:2525:3: error: template with C linkage
 2525 |   template<typename _MemPtr, typename _Arg, typename... _Args>
      |   ^~~~~~~~

The errors trace to glib, so I thought that maybe it needs to be included outside of the extern "C" block. I applied the following change:

--- a/src/gfsmlibs.h
+++ b/src/gfsmlibs.h
@@ -17,6 +17,7 @@
  */
 #ifndef GFSM_LIBRARIES_H_
 #define GFSM_LIBRARIES_H_
+#include<glib.h>
 extern "C" {
 #include<gfsm.h>
 #include<gfsmxl.h>

after which the code compiles. I don't know whether this is the correct solution though.

System info:

• Ubuntu 22.2
• g++ version: g++ (Ubuntu 11.2.0-19ubuntu1) 11.2.0
• glib package: libglib2.0-dev-bin/jammy,now 2.72.1-1 amd64