[gpsd-dev] [PATCH] libgps.h: Fix linkage problem

[Michal Privoznik]

When building with libQgpsmm=1 enabled I see this failure:

g++ -o libgps_core-qt.os -c -D_GNU_SOURCE -Wextra -Wall -Wno-uninitialized 
-Wno-missing-field-initializers -Wcast-align -Wmissing-declarations 
-Wmissing-prototypes -Wpointer-arith -Wreturn-type -pthread 
-Wmissing-declarations -O2 -pthread -fPIC -DUSE_QT -DQT_SHARED 
-I/usr/include/qt4 -I/usr/include/qt4/QtNetwork -I/usr/include/qt4/QtCore 
libgps_core.c
cc1plus: warning: command line option '-Wmissing-prototypes' is valid for 
C/ObjC but not for C++
In file included from libgps_core.c:19:0:
gps_json.h:41:28: error: conflicting declaration of 'int json_ais_read(const 
char*, char*, size_t, ais_t*, const char**)' with 'C' linkage
     /address@hidden@*/const char **);
                            ^
In file included from libgps_core.c:18:0:
libgps.h:34:12: note: previous declaration with 'C++' linkage
 extern int json_ais_read(const char *, char *, size_t, struct ais_t *,
            ^
scons: *** [libgps_core-qt.os] Error 1
scons: building terminated because of errors.

Digging more into the problem shows, libgps.h doesn't have the
functions enclosed within 'extern "C"' mark. Therefore, g++ mangled
the function names and hence the error.

Signed-off-by: Michal Privoznik <address@hidden>
---

I'm not sure if you allow long lines in commit messages, so feel
free to reword if needed.

Please note I'm not subscribed into the list so keep me CC'd.
Thanks.

 libgps.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/libgps.h b/libgps.h
index f773188..914c4df 100644
--- a/libgps.h
+++ b/libgps.h
@@ -10,6 +10,9 @@
 #define SHM_PSEUDO_FD  -1
 #define DBUS_PSEUDO_FD -2
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 extern int gps_sock_open(/address@hidden@*/const char *, 
/address@hidden@*/const char *,
                      /address@hidden@*/struct gps_data_t *);
 extern int gps_sock_close(struct gps_data_t *);
@@ -33,6 +36,9 @@ extern int gps_dbus_mainloop(struct gps_data_t *, int,
 
 extern int json_ais_read(const char *, char *, size_t, struct ais_t *,
                  /address@hidden@*/const char **);
+#ifdef __cplusplus
+}
+#endif
 
 #define PRIVATE(gpsdata) ((struct privdata_t *)(gpsdata)->privdata)
 
-- 
2.0.4