Mishandling of extern "C" {

[petervdonovan]

I'm not sure if this is in our power to fix -- it seems subtly related to the way the C/C++ highlighter that we delegate to works -- but it does not look good.

The following is highlighted correctly:

target C {
    threading: true,
    cmake-include: "include/federate__receiver_extension.cmake",
    keepalive: true,
    tracing: true,
    compile-definitions: {
        EXECUTABLE_PREAMBLE: "",
        WORKERS_NEEDED_FOR_FEDERATE: "2",
        NUMBER_OF_FEDERATES: "2",
        FEDERATED: "",
        FEDERATED_CENTRALIZED: ""
    },
    _fed_setup: "include/_federate__receiver_preamble.h"
}

preamble {=
    // #ifdef __cplusplus
    {
    // #endif
    #include "core/federated/federate.h"
    #include "core/federated/net_common.h"
    #include "core/federated/net_util.h"
    #include "core/federated/clock-sync.h"
    #include "core/threaded/reactor_threaded.h"
    #include "core/utils/util.h"
    extern federate_instance_t _fed;
    // #ifdef __cplusplus
    }
    // #endif
=}

reactor Receiver(
    stp_offset: time = 10 msec  // Used in the decentralized variant of the test
) {
    input in: int
    state reaction_invoked_correctly: bool = false

    reaction(in) {=
        lf_print("Received %d at (%lld, %u).",
                     in->value,
                     lf_time_logical_elapsed(),
                     lf_tag().microstep);
        if (lf_time_logical_elapsed() == USEC(1)) {
            lf_print("Requesting stop at (%lld, %u).",
                     lf_time_logical_elapsed(),
                     lf_tag().microstep);
            lf_request_stop();
            // The receiver should receive a message at tag
            // (1 usec, 1) and trigger this reaction
            self->reaction_invoked_correctly = true;
        }

        tag_t _1usec1 = (tag_t) { .time = USEC(1) + lf_time_start(), .microstep = 1u };
        if (lf_tag_compare(lf_tag(), _1usec1) > 0) {
            self->reaction_invoked_correctly = false;
        }
    =}

    reaction(shutdown) {=
        // Sender should have requested stop earlier than the receiver.
        // Therefore, the shutdown events must occur at (1000, 0) on the
        // receiver.
        if (lf_time_logical_elapsed() != USEC(1) ||
            lf_tag().microstep != 1) {
            lf_print_error_and_exit("Receiver failed to stop the federation at the right time. "
                    "Stopping at (%lld, %u).",
                     lf_time_logical_elapsed(),
                     lf_tag().microstep);
        } else if (self->reaction_invoked_correctly == false) {
            lf_print_error_and_exit("Receiver reaction(in) was not invoked the correct number of times. "
                    "Stopping at (%lld, %u).",
                     lf_time_logical_elapsed(),
                     lf_tag().microstep);
        }
        lf_print("SUCCESS: Successfully stopped the federation at (%lld, %u).",
                     lf_time_logical_elapsed(),
                     lf_tag().microstep);
    =}
}

reactor NetworkReceiver_0 {
    output msg: int

    logical action networkMessage_0: int

    reaction(networkMessage_0) -> msg {=
        msg->physical_time_of_arrival = self->_lf__networkMessage_0.physical_time_of_arrival;
        lf_set(msg, networkMessage_0->value);
    =}
}

@_fed_config(network_message_actions="networkMessage_0", dependencyPairs="")
main reactor {
    receiver = new Receiver()

    nr_federate__receiver = new NetworkReceiver_0()
    nr_federate__receiver.msg -> receiver.in
}

But the following is not handled correctly:

target C {
    threading: true,
    cmake-include: "include/federate__receiver_extension.cmake",
    keepalive: true,
    tracing: true,
    compile-definitions: {
        EXECUTABLE_PREAMBLE: "",
        WORKERS_NEEDED_FOR_FEDERATE: "2",
        NUMBER_OF_FEDERATES: "2",
        FEDERATED: "",
        FEDERATED_CENTRALIZED: ""
    },
    _fed_setup: "include/_federate__receiver_preamble.h"
}

preamble {=
    // #ifdef __cplusplus
    extern "C" {
    // #endif
    #include "core/federated/federate.h"
    #include "core/federated/net_common.h"
    #include "core/federated/net_util.h"
    #include "core/federated/clock-sync.h"
    #include "core/threaded/reactor_threaded.h"
    #include "core/utils/util.h"
    extern federate_instance_t _fed;
    // #ifdef __cplusplus
    }
    // #endif
=}

reactor Receiver(
    stp_offset: time = 10 msec  // Used in the decentralized variant of the test
) {
    input in: int
    state reaction_invoked_correctly: bool = false

    reaction(in) {=
        lf_print("Received %d at (%lld, %u).",
                     in->value,
                     lf_time_logical_elapsed(),
                     lf_tag().microstep);
        if (lf_time_logical_elapsed() == USEC(1)) {
            lf_print("Requesting stop at (%lld, %u).",
                     lf_time_logical_elapsed(),
                     lf_tag().microstep);
            lf_request_stop();
            // The receiver should receive a message at tag
            // (1 usec, 1) and trigger this reaction
            self->reaction_invoked_correctly = true;
        }

        tag_t _1usec1 = (tag_t) { .time = USEC(1) + lf_time_start(), .microstep = 1u };
        if (lf_tag_compare(lf_tag(), _1usec1) > 0) {
            self->reaction_invoked_correctly = false;
        }
    =}

    reaction(shutdown) {=
        // Sender should have requested stop earlier than the receiver.
        // Therefore, the shutdown events must occur at (1000, 0) on the
        // receiver.
        if (lf_time_logical_elapsed() != USEC(1) ||
            lf_tag().microstep != 1) {
            lf_print_error_and_exit("Receiver failed to stop the federation at the right time. "
                    "Stopping at (%lld, %u).",
                     lf_time_logical_elapsed(),
                     lf_tag().microstep);
        } else if (self->reaction_invoked_correctly == false) {
            lf_print_error_and_exit("Receiver reaction(in) was not invoked the correct number of times. "
                    "Stopping at (%lld, %u).",
                     lf_time_logical_elapsed(),
                     lf_tag().microstep);
        }
        lf_print("SUCCESS: Successfully stopped the federation at (%lld, %u).",
                     lf_time_logical_elapsed(),
                     lf_tag().microstep);
    =}
}

reactor NetworkReceiver_0 {
    output msg: int

    logical action networkMessage_0: int

    reaction(networkMessage_0) -> msg {=
        msg->physical_time_of_arrival = self->_lf__networkMessage_0.physical_time_of_arrival;
        lf_set(msg, networkMessage_0->value);
    =}
}

@_fed_config(network_message_actions="networkMessage_0", dependencyPairs="")
main reactor {
    receiver = new Receiver()

    nr_federate__receiver = new NetworkReceiver_0()
    nr_federate__receiver.msg -> receiver.in
}

The entire file after the preamble is highlighted as if it were plain C.

Note the extern "C" appearing in the preamble. That is the only difference.