need help, got a weird compilation error

[wxl374]

I have implemented a class called myTracer, and when I include my_tracer.h (without reference myTracer class) I got an error as follows:

In file included from ../include/opentelemetry/common/key_value_iterable.h:7:0,
from ../include/opentelemetry/common/key_value_iterable_view.h:10,
from ../include/opentelemetry/common/kv_properties.h:6,
from ../include/opentelemetry/baggage/baggage.h:8,
from ../include/opentelemetry/context/context_value.h:8,
from ../include/opentelemetry/context/context.h:7,
from ../include/opentelemetry/trace/tracer.h:6,
from my_tracer.h:3,
from *.h:22,
from .cpp:5:
../include/opentelemetry/nostd/function_ref.h:53:26: error: macro "F" requires 3 arguments, but only 1 given
return (F(callable_))(std::forward(args)...);
^
../include/opentelemetry/nostd/function_ref.h: In lambda function:
../include/opentelemetry/nostd/function_ref.h:53:53: error: expected ')' before '...' token
return (F(callable_))(std::forward(args)...);
^
../include/opentelemetry/nostd/function_ref.h:53:56: error: parameter packs not expanded with '...':
return (F(callable_))(std::forward(args)...);
^
../include/opentelemetry/nostd/function_ref.h:53:56: note: 'args'
../include/opentelemetry/nostd/function_ref.h:53:56: note: 'Args'
make: *** [.o] Error 1

• compilation options: -Wno-unused-local-typedefs -Wall -g -fPIC -std=c++11 -DSNAPPY -fopenmp -O0 -msse3 -mssse3 -DJSON_IS_AMALGAMATION -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -DJSON_IS_AMALGAMATION

• gcc verion: 4.8.3

• opentelemetry-cpp verion: v1.1.0 (include api/include/opentelemetry directory now)

and my code:

---

my_tracer.cpp
#include "opentelemetry/context/propagation/global_propagator.h"
#include "opentelemetry/trace/provider.h"

#include "tracer_common.h"
#include "my_tracer.h"

using namespace OPENTELEMETRY_NAMESPACE;

namespace my_namespace {

void myTracer::init(void)
{
// set global propagator
context::propagation::GlobalTextMapPropagator::SetGlobalPropagator(
nostd::shared_ptrcontext::propagation::TextMapPropagator(new trace::propagation::HttpTraceContext()));
}

nostd::shared_ptrtrace::Tracer myTracer::get_tracer(std::string tracer_name)
{
auto provider = trace::Provider::GetTracerProvider();
return provider->GetTracer(tracer_name);
}

nostd::shared_ptrtrace::Span myTracer::startSpan(std::map<std::string, std::string> &trace) {
trace::StartSpanOptions options;
options.kind = trace::SpanKind::kServer; // server
std::string span_name = "";

const my_namespace::HttpTextMapCarrier<std::map<std::string, std::string>> carrier(trace);
auto prop = context::propagation::GlobalTextMapPropagator::GetGlobalPropagator();
auto current_ctx = context::RuntimeContext::GetCurrent();
auto new_context = prop->Extract(carrier, current_ctx);
options.parent   = trace::GetSpan(new_context)->GetContext();

auto span = get_tracer("http-server")->StartSpan(span_name, {}, options);
auto scope = get_tracer("http_server")->WithActiveSpan(span);

return span;

}

void myTracer::endSpan(nostd::shared_ptrtrace::Span span) {
if (span != nullptr) {
span->End();
}
}
}

my_tracer.h
#pragma once

#include "opentelemetry/trace/tracer.h"

#include

using namespace OPENTELEMETRY_NAMESPACE;

namespace my_namespace {

class myTracer {
public:
void init(void);
nostd::shared_ptrtrace::Tracer get_tracer(std::string tracer_name);
nostd::shared_ptrtrace::Span startSpan(std::map<std::string, std::string> &trace);
void endSpan(nostd::shared_ptrtrace::Span span);
};
}

tracer_common.h
// Copyright The OpenTelemetry Authors
// SPDX-License-Identifier: Apache-2.0

#pragma once

#include "opentelemetry/context/propagation/text_map_propagator.h"
#include "opentelemetry/trace/propagation/http_trace_context.h"

using namespace OPENTELEMETRY_NAMESPACE;

namespace my_namespace {

template
class HttpTextMapCarrier : public context::propagation::TextMapCarrier {
public:
HttpTextMapCarrier(T &headers) : headers_(headers) {}
HttpTextMapCarrier() = default;

nostd::string_view Get(nostd::string_view key) const noexcept override {
    std::string key_to_compare = key.data();
    if (key == trace::propagation::kTraceParent) {
        key_to_compare = "Traceparent";
    }
    else if (key == trace::propagation::kTraceState) {
        key_to_compare = "Tracestate";
    }
    auto it = headers_.find(key_to_compare);
    if (it != headers_.end()) {
        return it->second;
    }
    return "";
}

void Set(nostd::string_view key, nostd::string_view value) noexcept override {
    headers_.insert(std::pair<std::string, std::string>(std::string(key), std::string(value)));
}

T headers_;

};
} // namespace

---

I attempt to write a snippet to test my code (include my_tracer.h, reference class and call class member functions), it worked with no error (the code is at the end). I still comfused with the previous error which is reported in function_ref.h. Does anyone know how to solve this error?

my test code, it worked
compilation options: gcc -g -lstdc++ -std=c++11 -pthread -Wl,--no-as-needed my_tracer.cpp main.cpp -I ../../include -o test
with the same gcc and opentelemetry-cpp verions

main.cpp
#include "my_tracer.h"

using namespace OPENTELEMETRY_NAMESPACE;
using namespace my_namespace;

int main(void) {
myTracer tracer;
tracer.init();
std::map<std::string, std::string> map;
map.insert(std::make_pair("traceParent", ""));
auto span = tracer.startSpan(map);
tracer.endSpan(span);
return 0;
}

[lalitb]

Not sure of the error, as the CI build using gcc 4.8 works fine. Could it be the one of the gcc compile option causing the error:

compilation options: -Wno-unused-local-typedefs -Wall -g -fPIC -std=c++11 -DSNAPPY -fopenmp -O0 -msse3 -mssse3 -DJSON_IS_AMALGAMATION -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -DJSON_IS_AMALGAMATION

[wxl374]

Thanks for your reply... and finally I found the reason... there is another macro called "F" in my project and after preprocessor the local "F" is replaced by the macro.