Linking in C++ compilers (including g++) causes references to be created
with their arguments. Due to this, trace library headers included into
C++ code base will cause their objects to built with symbols with
arguments. Apparently this is to support operator overloading in C++.
This causes linker errors. For example, here's what I get when I try to
link libtraceevent with a main.o built from a C++ main.cc source file.
main.cc:(.text+0x90):
undefined reference to `trace_seq_init(trace_seq*)'
undefined reference to `trace_seq_do_printf(trace_seq*)'
undefined reference to `tep_event_fields(tep_event*)'
The standard fix for this is to wrap the C project's header in
extern "C".
With this patch, I am able to link libtraceevent into a C++
code base.
Signed-off-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
---
include/traceevent/event-parse.h | 8 ++++++++
include/traceevent/trace-seq.h | 8 ++++++++
2 files changed, 16 insertions(+)
diff --git a/include/traceevent/event-parse.h b/include/traceevent/event-parse.h
index 0b911e1..9d7634e 100644
--- a/include/traceevent/event-parse.h
+++ b/include/traceevent/event-parse.h
@@ -14,6 +14,10 @@
#include "trace-seq.h"
+#ifdef __cplusplus
+extern "C" {
+#endif
+
#ifndef __maybe_unused
#define __maybe_unused __attribute__((unused))
#endif
@@ -778,4 +782,8 @@ void tep_set_loglevel(enum tep_loglevel level);
void tep_print_field(struct trace_seq *s, void *data,
struct tep_format_field *field);
+#ifdef __cplusplus
+}
+#endif
+
#endif /* _PARSE_EVENTS_H */
diff --git a/include/traceevent/trace-seq.h b/include/traceevent/trace-seq.h
index d68ec69..217492f 100644
--- a/include/traceevent/trace-seq.h
+++ b/include/traceevent/trace-seq.h
@@ -10,6 +10,10 @@
#include <stdarg.h>
#include <stdio.h>
+#ifdef __cplusplus
+extern "C" {
+#endif
+
/* ----------------------- trace_seq ----------------------- */
#ifndef TRACE_SEQ_BUF_SIZE
@@ -52,4 +56,8 @@ extern void trace_seq_terminate(struct trace_seq *s);
extern int trace_seq_do_fprintf(struct trace_seq *s, FILE *fp);
extern int trace_seq_do_printf(struct trace_seq *s);
+#ifdef __cplusplus
+}
+#endif
+
#endif /* _TRACE_SEQ_H */
--
2.25.1
|