stdexec — Senders for C++
A reference implementation of std::execution ([exec]), the C++26 model for asynchronous and parallel programming.
stdexec lets you express asynchronous work as composable, lazy sender pipelines that can run on threads, thread pools, GPUs, or any custom execution context — with structured concurrency guarantees.
[!WARNING]
stdexec is experimental and tracks an evolving standard. APIs may change without notice. NVIDIA does not guarantee fitness for any particular purpose.
Table of contents
Example
Run three pieces of work concurrently on the system thread pool. Try it live on godbolt.
#include <stdexec/execution.hpp>
#include <cstdio>
namespace ex = stdexec;
int main() {
auto sched = ex::get_parallel_scheduler();
auto fun = [](int i) { return i * i; };
// Build a lazy pipeline: three squares, computed in parallel.
auto work = ex::when_all(ex::on(sched, ex::just(0) | ex::then(fun)),
ex::on(sched, ex::just(1) | ex::then(fun)),
ex::on(sched, ex::just(2) | ex::then(fun)));
// Launch the work and wait for the result.
auto [i, j, k] = ex::sync_wait(std::move(work)).value();
std::printf("%d %d %d\n", i, j, k); // prints "0 1 4"
}
get_parallel_scheduler() needs its backend compiled in, so either define STDEXEC_PARALLEL_SCHEDULER_HEADER_ONLY for your target (as the godbolt link does), or configure stdexec with -DSTDEXEC_BUILD_PARALLEL_SCHEDULER=ON and link STDEXEC::parallel_scheduler. Without either, the program can still link and then crash on that call.
Features
- C++26 reference implementation of
std::execution (P2300).
- Header-only, no external dependencies.
- Composable algorithms:
then, let_value, when_all, bulk, split, transfer, upon_*, ...
- Structured concurrency primitives:
async_scope, task, finally, when_any, repeat_n, ...
- Pluggable schedulers: system parallel scheduler, static thread pool, Linux
io_uring context, NVIDIA GPU contexts, your own.
- GPU offload via
nvexec schedulers (nvc++ compiler).
- Coroutine interop: senders are awaitable; awaitables are senders.
- Generic extensions (
<exec/...>) for primitives not (yet) in the standard.
Compiler support
| Compiler | Minimum version | Notes |
|---|
| GCC | 12 | |
| Clang | 16 | |
| MSVC | 14.43 | |
| Xcode (Apple Clang) | 16 | |
| nvc++ | 26.5 | required for GPU support |
Requires -std=c++20 or later.
[!NOTE]
stdexec does not yet support NVIDIA's nvcc compiler.
Installation
Pick whichever fits your project.
CPM (recommended)
CPM fetches and configures stdexec automatically from your CMakeLists.txt:
CPMAddPackage(
NAME stdexec
GITHUB_REPOSITORY NVIDIA/stdexec
GIT_TAG main # or a specific tag
)
target_link_libraries(my_target PRIVATE STDEXEC::stdexec)
add_subdirectory
Clone alongside your project and add it as a subdirectory:
git clone https://github.com/NVIDIA/stdexec.git
add_subdirectory(stdexec)
target_link_libraries(my_target PRIVATE STDEXEC::stdexec)
Conan
A conanfile.py is provided for use with the Conan package manager.
NVIDIA HPC SDK
Starting with NVHPC SDK 22.11, stdexec is bundled with nvc++. Pass --experimental-stdpar to put stdexec headers on the include path. Add -stdpar=gpu for GPU features. See the godbolt example.
Manual include path
stdexec is header-only, so adding -I<stdexec root>/include to your compile command is sufficient. Using the CMake target is recommended because it sets the required compile flags.
Quick start
A minimal CMakeLists.txt using CPM:
cmake_minimum_required(VERSION 3.25.0)
project(stdexec_example LANGUAGES CXX)
include(CPM.cmake) # see https://github.com/cpm-cmake/CPM.cmake#adding-cpm
CPMAddPackage(
NAME stdexec
GITHUB_REPOSITORY NVIDIA/stdexec
GIT_TAG main
)
add_executable(example example.cpp)
target_link_libraries(example PRIVATE STDEXEC::stdexec)
GPU support
stdexec ships GPU schedulers in <nvexec/...> for use with nvc++ -stdpar=gpu:
This is the beginning of the README. Read the rest at the original. Read the full README ↗
