ITT API C++ Wrapper

A modern, header-only C++ wrapper for the ITT API instrumentation library. The wrapper provides RAII-based scoped helpers and type-safe C++ abstractions over the existing C API.

Supported APIs

Requirements

• C++17 or later
• The existing ittnotify static C-library

Including the Wrapper

Use the umbrella header to get the full API:

#include <ittapi.hpp>

Or include individual headers:

#include <ittapi_domain.hpp>
#include <ittapi_task.hpp>
#include <ittapi_collection_control.hpp>

Example: Task Instrumentation

#include <ittapi.hpp>

#include <chrono>
#include <thread>

int main() {
    ittapi::set_thread_name("main");
    ittapi::Domain domain{"example.task"};
    ittapi::StringHandle task_name{"process"};

    ittapi::pause();
    ittapi::resume();

    {
        auto task = domain.task(task_name);
        std::this_thread::sleep_for(std::chrono::milliseconds(10));
    }

    return 0;
}

Linking

CMake Consumer

find_package(ittapi CONFIG REQUIRED)
target_link_libraries(my_app PRIVATE ittapi::cxx)

The ittapi::cxx target is an INTERFACE library that transitively links the existing ittnotify static library and adds the C++ wrapper include directories.

Manual GCC/G++ (Linux)

g++ -std=c++17 -O2 \
    -I<ittapi-install-prefix>/include \
    app.cpp \
    <ittapi-install-prefix>/lib/libittnotify.a \
    -ldl -pthread \
    -o app

Building with CMake

From the repository root:

cmake -B build -DCMAKE_BUILD_TYPE=Release -DITT_API_CPP_SUPPORT=ON
cmake --build build

The ITT_API_CPP_SUPPORT option is OFF by default.

You can also build with the build script:

python buildall.py --cpp

Running Tests

Tests are registered inside the cpp/ subdirectory. After building:

ctest --test-dir build/cpp --output-on-failure

Performance Tips

• Pre-create StringHandle objects for task/region names used in hot paths. The StringHandle overloads pass a raw pointer with no locking — this is the zero-overhead path.

  // Do this once at startup:
  ittapi::StringHandle name{"compute"};
  
  // Then in hot code:
  auto task = domain.task(name);  // no allocation, no lock
  

• The string_view overloads are convenient but allocate a std::string on cache miss and acquire a lock in the C library. Use them for setup or infrequent tasks, not tight loops.
• Create Domain objects once and reuse them. Domain creation is a global lookup — store them as class members or globals, not as function locals called repeatedly.
• Use overlapped tasks (with IDs) only when you need tasks that end out of order. Stack-based tasks (without IDs) are simpler and carry less internal state.

API Reference

Free Functions

• ittapi::pause() — Pause collection.
• ittapi::resume() — Resume collection.
• ittapi::set_thread_name(std::string_view name) — Set the current thread's name.

Classes

ittapi::StringHandle

Lightweight wrapper around __itt_string_handle*.

ittapi::StringHandle h{"my_handle"};
h.valid();  // true if handle was created
h.get();    // underlying __itt_string_handle*

ittapi::Domain

Lightweight wrapper around __itt_domain* with convenience factories.

ittapi::Domain d{"my.domain"};
auto task   = d.task("task_name");     // returns ScopedTask (RAII)
auto region = d.region("region_name"); // returns ScopedRegion
auto frame  = d.frame();               // returns ScopedFrame

d.task_begin("work");                  // manual task begin (simple stack-based task)
d.task_end();                          // manual task end

__itt_id id = __itt_id_make(nullptr, 1);
d.task_begin("overlapped", id, __itt_null);  // manual task begin (overlapped task)
d.task_end(id);                              // manual task end by ID

ittapi::ScopedTask

RAII wrapper for task begin/end. Use domain.overlapped_task() to create an overlapped task (tasks that can end in any order). Each overlapped task instance gets a unique __itt_id derived from its object address. The id() method returns this ID.

// Simple task
{
    auto task = domain.task("work");
    // ... do work ...
    task.end();     // optional early end (idempotent)
}                   // destructor ends task if still active

Overlapped tasks — use overlapped_task(), optionally pass a parent ID:

{
    auto parent = domain.overlapped_task("parent");               // overlapped, no parent
    auto child  = domain.overlapped_task("child", parent.id());   // overlapped, child of parent

    parent.end();  // end parent task while child is still running
    child.end();   // child task ends
}

For manual (non-RAII) control:

domain.task_begin("work");
// ... do work ...
domain.task_end();

// overlapped tasks:
__itt_id id = __itt_id_make(nullptr, 1);
domain.task_begin("overlapped_work", id, __itt_null);
// ... do work ...
domain.task_end(id);

ittapi::ScopedRegion

RAII wrapper for region begin/end.

ittapi::ScopedFrame

RAII wrapper for frame begin/end. Supports explicit timestamp submission.

ittapi::ScopedFrame::submit(domain.get(), begin_ts, end_ts);

ittapi::ScopedPause

RAII wrapper for pause/resume. Constructor pauses, destructor resumes.

{
    ittapi::ScopedPause sp;
    // collection is paused
    sp.resume_now();  // optional early resume
}