coverage: fix build with g++

Guard the coverage-related shenanigans from g++ when building the one
C++ unit test we have, so we don't have to make it C++ compatible:

[1573/2109] Compiling C++ object test-bus-vtable-cc.p/src_libsystemd_sd-bus_test-bus-vtable-cc.cc.o
FAILED: test-bus-vtable-cc.p/src_libsystemd_sd-bus_test-bus-vtable-cc.cc.o
ccache c++ -Itest-bus-vtable-cc. ... -c ../src/libsystemd/sd-bus/test-bus-vtable-cc.cc
In file included from <command-line>:
../src/basic/coverage.h:17:15: error: ‘_Noreturn’ does not name a type
   17 | static inline _Noreturn void _coverage__exit(int status) {
      |               ^~~~~~~~~
../src/basic/coverage.h:46:29: error: conflicting declaration of ‘int _coverage_execveat(int, const char*, char* const*, char* const*, int)’ with ‘C’ linkage
   46 | #define execveat(d,p,a,e,f) _coverage_execveat(d, p, a, e, f)
      |                             ^~~~~~~~~~~~~~~~~~
../src/basic/coverage.h:34:19: note: previous declaration with ‘C++’ linkage
   34 | static inline int _coverage_execveat(
      |                   ^~~~~~~~~~~~~~~~~~
../src/basic/coverage.h:46:29: error: declaration of ‘int _coverage_execveat(int, const char*, char* const*, char* const*, int) noexcept’ has a different exception specifier
   46 | #define execveat(d,p,a,e,f) _coverage_execveat(d, p, a, e, f)
      |                             ^~~~~~~~~~~~~~~~~~
../src/basic/coverage.h:34:19: note: from previous declaration ‘int _coverage_execveat(int, const char*, char* const*, char* const*, int)’
   34 | static inline int _coverage_execveat(
      |                   ^~~~~~~~~~~~~~~~~~
../src/basic/coverage.h:58:24: error: conflicting declaration of ‘int _coverage_execvpe(const char*, char* const*, char* const*)’ with ‘C’ linkage
   58 | #define execvpe(f,a,e) _coverage_execvpe(f, a, e)
      |                        ^~~~~~~~~~~~~~~~~
../src/basic/coverage.h:48:19: note: previous declaration with ‘C++’ linkage
   48 | static inline int _coverage_execvpe(
      |                   ^~~~~~~~~~~~~~~~~
../src/basic/coverage.h:58:24: error: declaration of ‘int _coverage_execvpe(const char*, char* const*, char* const*) noexcept’ has a different exception specifier
   58 | #define execvpe(f,a,e) _coverage_execvpe(f, a, e)
      |                        ^~~~~~~~~~~~~~~~~
../src/basic/coverage.h:48:19: note: from previous declaration ‘int _coverage_execvpe(const char*, char* const*, char* const*)’
   48 | static inline int _coverage_execvpe(
      |                   ^~~~~~~~~~~~~~~~~
[1582/2109] Compiling C object test-event.p/src_libsystemd_sd-event_test-event.c.o
ninja: build stopped: subcommand failed.

diff --git a/src/basic/coverage.h b/src/basic/coverage.h
index 2c3ff12efebad370b4f05d7d284287434997c0db..5c30482e580e135dd8c945e4ec59a53fff5ef4c1 100644 (file)
--- a/src/basic/coverage.h
+++ b/src/basic/coverage.h
@@ -1,8 +1,14 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-extern void __gcov_dump(void);
-extern void __gcov_reset(void);
+/* Use the coverage-related tweaks below only for C stuff as they're not really
+ * C++ compatible, and the only thing that is built with a C++ compiler is
+ * the lone test-bus-vtable-cc unit test.
+ */
+#ifndef __cplusplus
+
+void __gcov_dump(void);
+void __gcov_reset(void);
 
 /* When built with --coverage (gcov) we need to explicitly call __gcov_dump()
  * in places where we use _exit(), since _exit() skips at-exit hooks resulting
@@ -12,7 +18,7 @@ extern void __gcov_reset(void);
  * explicitly on the compiler command line via the -include directive (only
  * when built with -Db_coverage=true)
  */
-extern void _exit(int);
+void _exit(int);
 
 static inline _Noreturn void _coverage__exit(int status) {
         __gcov_dump();
@@ -28,8 +34,8 @@ static inline _Noreturn void _coverage__exit(int status) {
  * [0] https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=libgcc/libgcov-interface.c;h=b2ee930864183b78c8826255183ca86e15e21ded;hb=HEAD
  */
 
-extern int execveat(int, const char *, char * const [], char * const [], int);
-extern int execvpe(const char *, char * const [], char * const []);
+int execveat(int, const char *, char * const [], char * const [], int);
+int execvpe(const char *, char * const [], char * const []);
 
 static inline int _coverage_execveat(
                         int dirfd,
@@ -56,3 +62,5 @@ static inline int _coverage_execvpe(
         return r;
 }
 #define execvpe(f,a,e) _coverage_execvpe(f, a, e)
+
+#endif