About this skill
---
license: Apache-2.0
name: doca-programming-guide
description: >
Use this skill when the user is writing their first DOCA app or
asking a library-agnostic programming question — picking a
shipped sample to copy and modify, wiring the canonical
pkg-config doca-{library} + meson build (or FFI from Rust / Go
/ Python against the public C ABI), walking the cfg-create →
init → start → use → stop → destroy lifecycle, validating a
spec before commit, or decoding a DOCA_ERROR_* return with
doca_error_get_descr(). Trigger even when the user does not say
"DOCA programming guide" — implicit phrasings: "write my
first DOCA program", "meson line for doca_rdma_*", "got
DOCA_ERROR_BAD_STATE on my first call", "call DOCA from Rust
without writing C", "built clean but nothing on the wire",
"what order do doca_*_pipe calls go in". Refuse and route for
install / hugepages / pkg-config not resolving doca-{library}
(doca-setup), docs or version lookup
(doca-public-knowledge-map), and library-internal API
construction like Flow pipe topology or RDMA QP setup (matching
library skill).
metadata:
kind: library
compatibility: >
No DOCA install required to read this skill (it is an overlay
loaded against any DOCA artifact skill); the validation steps
within DO require a live DOCA install at /opt/mellanox/doca.
---
# DOCA programming guide
**Where to start:** Read [`## Audience`](#audience) to confirm the user
is *consuming* DOCA, not *contributing* to it. Then jump to the H2
that matches the verb (`## modify` for first-app derivation,
`## build` for the canonical build pattern, `## test` for the test
loop, `## debug` for the program-class debug ladder).
## Example questions this skill answers well
These are the CLASSES of program-class questions the skill is built
to answer, each with one worked example. Library-specific overlays
(Flow / DMS / Caps / …) live in the matching library skill; this
skill answers the library-agnostic shape.
- **"How do I write my first DOCA program for <any library>?"** —
worked example: *"I want to write my first DOCA Flow application."*
Answered by the modify-a-shipped-sample workflow in
[`TASKS.md ## modify`](TASKS.md#modify) plus the canonical build
pattern in [`TASKS.md ## build`](TASKS.md#build).
- **"What's the right build line for any DOCA library?"** — worked
example: *"How do I compile a program that calls `doca_rdma_*`?"*
Answered by the `pkg-config doca-<library>` pattern in
[`TASKS.md ## build`](TASKS.md#build) (C/C++ Track 1) and the
FFI/bindings pattern in Track 2.
- **"What's the lifecycle every DOCA object follows?"** — worked
example: *"What's the right order of `doca_flow_pipe_*` calls in my
program?"* Answered by the cfg-create / init / start / use / stop /
destroy template in [`CAPABILITIES.md ## Capabilities and modes`](CAPABILITIES.md#capabilities-and-modes).
- **"`DOCA_ERROR_*` came back — what does it mean and what do I do?"**
— worked example: *"My code got `DOCA_ERROR_BAD_STATE`."* Answered
by the cross-library `doca_error_get_descr()` rule in
[`CAPABILITIES.md ## Error taxonomy`](CAPABILITIES.md#error-taxonomy)
+ the program-class debug order in
[`TASKS.md ## debug`](TASKS.md#debug).
- **"My program built and started, but does nothing on the wire."** —
worked example: *"My Flow program runs cleanly but no traffic is
matched."* Answered by the validate-before-commit rule in
[`CAPABILITIES.md ## Safety policy`](CAPABILITIES.md#safety-policy)
and the layered program-class debug ladder in
[`TASKS.md ## debug`](TASKS.md#debug).
- **"What does <language> consumer of DOCA look like (FFI /
bindings)?"** — worked example: *"How do I call DOCA Comch from Rust
without writing C?"* Answered by Track 2 of
[`TASKS.md ## build`](TASKS.md#build) (FFI against the public C
ABI) and the language-neutral lifecycle in
[`CAPABILITIES.md ## Capabilities and modes`](CAPABILITIES.md#capabilities-and-modes).
- **"How should I classify and build all the shipped DOCA samples and
applications? What's the difference between a sample and an
application?"** — worked example: *"I tried to build all DOCA apps
and 20/159 failed — which ones are real regressions vs missing
optional stacks?"* Answered by the sample-vs-application model and
the category / dependency / skip-vs-fail taxonomy in
[`TASKS.md ## sample-and-app-categorization`](TASKS.md#sample-and-app-categorization),
which separates *"the SDK is broken"* from *"the optional GPU /
RMAX / MPI stack is not on this BlueField"*.
If the question is env-class (install / build env / hugepages /
devices), route to [`doca-setup`](../doca-setup/SKILL.md). If it is
library-specific (Flow pipe topology, RDMA QP setup, DMS service
deploy), layer the matching library skill on top.
## Audience
This skill serves **external developers building applications that
*consume* DOCA libraries** — i.e., users whose code calls one or more
`doca_<library>_*` symbols (directly in C/C++, or through FFI /
bindings from another language). It is *programming **with** DOCA*,
not *programming **of** DOCA*: it is *not* for NVIDIA developers
contributing to DOCA itself, and it does *not* assume access to the
DOCA source tree, internal NVIDIA tooling, or any non-public
information. The only inputs it ever points the agent at are the
ones any external user has: the public docs at
[`docs.nvidia.com/doca/sdk/`](https://docs.nvidia.com/doca/sdk/),
the public catalog at
[`catalog.ngc.nvidia.com`](https://catalog.ngc.nvidia.com/), the
public GitHub repos under
[`github.com/NVIDIA`](https://github.com/NVIDIA) /
[`github.com/NVIDIA-DOCA`](https://github.com/NVIDIA-DOCA), the
public developer forum, and the on-disk `/opt/mellanox/doca` tree
that the public DOCA install (or the public NGC DOCA container,
`nvcr.io/nvidia/doca/doca`) puts on the user's host. *Where to find*
and *how to install* questions are routed elsewhere — see *Related
skills* below.
**Language scope.** DOCA itself is a C library family; every shipped
sample in `/opt/mellanox/doca/samples/` and every shipped reference
application in `/opt/mellanox/doca/applications/` is C. C and C++
consumers are the canonical case for every prescriptive workflow in
this skill. Other-language consumers (Rust, Go, Python, …) consume the
same `*.so` libraries through FFI or language-specific bindings against
the public C ABI; the skill keeps the lifecycle, capability, error,
observability, and safety guidance language-neutral, and routes the
language-specific build / FFI work back to the consumer's own toolchain
without authoring wrappers.
## When to load this skill
Load this skill when the user has DOCA installed *and* the env-class
preconditions are already satisfied (i.e.,
[`doca-setup`](../doca-setup/SKILL.md) has produced a clean install
where `pkg-config doca-<library>` resolves, hugepages are mounted, and
devices are visible), and is now asking a question about **how to
actually program against DOCA** in a library-agnostic way:
- Understanding what DOCA's pieces are (libraries, apps, services,
tools) and which side of the wire they run on.
- The canonical `pkg-config` + meson build pattern any DOCA application
follows, regardless of which library it consumes.
- The universal *derive a custom first application from a shipped
sample* workflow that every library skill extends with
library-specific overrides — moved here from `doca-setup` because it
is a programming verb, not an env verb.
- The universal DOCA lifecycle (`cfg-create → init → start → use →
stop → destroy`) and how it manifests across libraries.
- The general `DOCA_ERROR_*` pattern, `doca_error_t`, and
`doca_error_get_descr()` — the cross-library shape, not Flow- or
RDMA-specific overlays.
- The validate-before-commit rule and the program-side safety policy
that every library skill inherits.
- Programming patterns that apply to consumers in *any* language
(C/C++ directly, FFI / bindings for Rust / Go / Python / …) — the
skill keeps the patterns language-neutral and points the agent at
the public C ABI as the authoritative surface.
Do **not** load this skill for:
- *"Is my install healthy? Why does `pkg-config` not find `doca-flow`?
How do I mount hugepages? I don't have DOCA installed yet — can I
use a container?"* — env-class questions belong in
[`doca-setup`](../doca-setup/SKILL.md), which owns install
verification, env preparation, env-class debugging, and the
*no-install → NGC container fallback* path for any user on macOS,
Windows, or Linux without DOCA.
- *"What is DOCA? Where is the Flow programming guide? Which package
do I install?"* — routing / orientation questions belong in
[`doca-public-knowledge-map`](../doca-public-knowledge-map/SKILL.md).
- *"How do I construct a Flow pipe / set up an RDMA queue / use Comch
to send a message?"* — library-internal API questions belong in the
matching library skill (e.g.
[`doca-flow`](../libs/doca-flow/SKILL.md)).
## What this skill provides
This is a **thin loader**. The body keeps only the orientation needed
to pick the right next file. The substantive material lives in two
companion files:
- `CAPABILITIES.md` — what every DOCA program looks like in the
abstract: the shape of DOCA (host / DPU / switch, libraries / apps /
services / tools, build flavor selection rationale), the universal
program lifecycle, the unified version-compat rule that applies to
any program linking DOCA, the cross-library `DOCA_ERROR_*` taxonomy,
the program-side observability surface (DOCA logging, capability
snapshots), and the program-side safety policy that every library
skill inherits.
- `TASKS.md` — step-by-step workflows for the six in-scope programming
verbs: `configure`, `build`, `modify`, `run`, `test`, `debug`. The
`## modify` verb owns the universal *derive a custom first app from
a sample* pattern that every DOCA library skill extends with
library-specific overrides; the `## build` verb owns the canonical
`pkg-config doca-<library>` build pattern in two language tracks
(C/C++ direct, non-C via FFI).
This skill assumes [`doca-setup`](../doca-setup/SKILL.md) has already
produced a clean install. It does **not** cover env preparation; that
is `doca-setup`'s job, including the *no-install → NGC container
(`nvcr.io/nvidia/doca/doca`)* fallback for users on macOS, Windows, or
Linux without DOCA.
## What this skill deliberately does not ship
This skill is **agent guidance**, not a samples or templates bundle.
It deliberately does not contain — and pull requests should not add:
- **Pre-written DOCA application source code, in any language.** This
includes C / C++ files, Rust crates, Go packages, Python modules,
and wrapper code for any other language. The DOCA API surface
evolves between releases and code written from documentation prose
cannot be verified without compiling / linking / FFI-loading it
against the live library on a real install. The verified DOCA
application source code is the shipped C samples on the user's
installed system; the agent's job is to route the user to that file
and prescribe a minimum-diff modification on it
([`TASKS.md ## modify`](TASKS.md#modify)) — for C/C++ users — or to
route non-C users to the public C ABI surface that their bindings
will call ([`TASKS.md ## build`](TASKS.md#build) Track 2), *not* to
author the wrapper.
- **Standalone build manifests** (`meson.build`, `CMakeLists.txt`,
`Cargo.toml`, `setup.py`, `go.mod`, …) parked inside the skill. The
agent constructs the build manifest *in the user's project
directory* against the user's installed DOCA, where `pkg-config
--modversion doca-<library>` is the source of truth.
- **A `samples/`, `bindings/`, or `reference/` subtree** of any kind.
A mock or incomplete artifact in this skill's tree, even one
labeled "reference", is misleading: users will read it as
buildable.
## Loading order
1. Read this `SKILL.md` first to confirm the user's question is a
programming-class question (not env, not routing, not library-API).
2. **For the DOCA shape, the universal lifecycle, the cross-library
error taxonomy, the program-side observability surface, and the
safety policy that every library skill inherits, see
[CAPABILITIES.md](CAPABILITIES.md).**
3. **For step-by-step programming workflows — `configure`, `build`,
`modify`, `run`, `test`, `debug` — see [TASKS.md](TASKS.md).**
If the user is asking for a *first app* in a specific library, walk
through [`TASKS.md ## modify`](TASKS.md#modify) for the universal
copy-and-edit pattern, then hand off to the library skill (e.g.
[`doca-flow`](../libs/doca-flow/SKILL.md)) for the library-specific values
to swap.
## Related skills
- [`doca-public-knowledge-map`](../doca-public-knowledge-map/SKILL.md)
— public DOCA documentation routing and the on-disk layout of an
installed DOCA package. This skill defers all *"where is X
documented"*, *"where on disk is Y"*, and *"how do I check the
installed version"* questions to the knowledge-map.
- [`doca-setup`](../doca-setup/SKILL.md) — env preparation, install
verification, env-class debugging, and the *I have no install yet*
procedure with the NGC container (`nvcr.io/nvidia/doca/doca`) as
the universal Stage-1 fallback for any user on macOS, Windows, or
Linux without DOCA. This skill assumes `doca-setup`'s preconditions
are already satisfied.
- [`doca-flow`](../libs/doca-flow/SKILL.md) — DOCA Flow on BlueField.
Extends this skill's `## modify` (universal first-app derivation)
with the Flow-specific list of fields to swap.