cross-compile

name	cross-compile
description	Cross-compile a hailo-media-library app for the H15 SBC using the Yocto SDK on the host. Use when the user has modified main.cpp (e.g. via /swap-model) and needs an aarch64 binary, or asks "build it for the board". Does NOT require building the whole library tree — links against the prebuilt libs in the SDK sysroot.
tools	Bash, Read, Glob

/cross-compile — build aarch64 binary for the H15 SBC

The Yocto SDK ships a full sysroot with all hailo-media-library libs prebuilt. For a single-app rebuild (typical case after /swap-model or any small main.cpp change), you do not need to build the whole library — just compile the one source file against the SDK's sysroot.

Inputs

• Path to the modified source file.
• Optional: target board (h15h vs h15l). Default to whichever SDK is installed on the host.

Procedure

1. Locate the SDK. Look for environment-setup-armv8a-poky-linux somewhere under the user's working area.

   /opt/poky/4.0.23/                    # default install location
   

   If the search fails (no environment-setup-armv8a-poky-linux found in the usual places), ask the user where the toolchain is located before proceeding — do not assume a path or jump to installing a new SDK. Only if the user confirms no SDK is installed, install it from the BSP package — look for .../prebuilt/sbc/sdk/poky-glibc-x86_64-core-image-minimal-armv8a-hailo15<arch>-sbc-toolchain-*.sh. It's a 2.5 GB self-extractor:

   <installer>.sh -y -d <destination-path>
   

   Install time is several minutes.

2. Source the env. This sets CC, CXX, CXXFLAGS, PKG_CONFIG_PATH, PKG_CONFIG_SYSROOT_DIR, etc.

   . <sdk>/environment-setup-armv8a-poky-linux
   

   $CXX will be aarch64-poky-linux-g++ plus a long list of hardening flags and --sysroot=$SDKTARGETSYSROOT.

3. Compile. A single-file build needs:

   $CXX $CXXFLAGS -std=c++20 -DPERFETTO_NOT_FOUND \
     $(pkg-config --cflags hailo-analytics hailo-medialib gstreamer-1.0 gstreamer-app-1.0 spdlog) \
     main.cpp -o <app_name>.aarch64 \
     $(pkg-config --libs hailo-analytics hailo-medialib gstreamer-1.0 gstreamer-app-1.0 spdlog) \
     -lpthread
   

   Pick <app_name> based on the source — e.g. the case-study name, or whatever the user calls the demo.

   • The perfetto define -DPERFETTO_NOT_FOUND must match the library build, otherwise headers #error.
   • gstreamer pkg-configs are load-bearing even if main.cpp has no <gst/gst.h> — analytics headers pull it in transitively.

4. Verify the artifact.

   file <app_name>.aarch64
   # → ELF 64-bit LSB pie executable, ARM aarch64, …
   

5. Hand off to /deploy.

When to build the whole tree instead

If the user changed something inside hailo_analytics_api/, media_library/, or hailo-postprocess/ — i.e. a library, not just a top-level main.cpp — single-file compile won't help; the library needs rebuilding. The Media Library User Guide §6 documents the canonical Meson flow: source the SDK env first (so CC/CXX/PKG_CONFIG_PATH point at the cross toolchain), then run meson with the -Dplatform= flag matching the target board. The -Dplatform flag is required and board-specific — defaults to 15h, so H15L users must pass 15l explicitly or they'll get the wrong binary.

Each tree has a slightly different build, all per §6.2–§6.4:

. <sdk>/environment-setup-armv8a-poky-linux

# hailo-media-library (§6.2)
cd hailo-media-library
meson setup build --buildtype=release --prefix=/usr -Dplatform=15h   # or -Dplatform=15l
ninja -C build
DESTDIR=/tmp/install ninja -C build install
scp -r /tmp/install/* root@<target-ip>:/

# hailo-analytics (§6.3) — heavier, can OOM
cd hailo-analytics
meson setup build --buildtype=release --prefix=/usr -Dplatform=15h \
  -Dapps_install_dir=/home/root/apps
ninja -C build -j 10 -l 10           # job-limit prevents memory exhaustion
DESTDIR=/tmp/install ninja -C build install
scp -r /tmp/install/* root@<target-ip>:/

# hailo-postprocess (§6.4)
cd hailo-postprocess
meson setup build --buildtype=release --prefix=/usr -Dplatform=15h \
  -Dpost_processes_install_dir=/usr/lib/hailo-post-processes/
ninja -C build
DESTDIR=/tmp/install ninja -C build install
scp -r /tmp/install/* root@<target-ip>:/

This is many minutes and produces .so files that also need to be deployed (replacing /usr/lib/libhailo_analytics.so.1.11.0 etc on the board). Confirm with the user before going down that path — it's heavier. (soon there will be a /build skill for that. check if that exists already)

Gotchas

• meson and pkg-config from the SDK come from sysroots/x86_64-pokysdk-linux/usr/bin/. Sourcing the env script puts them on PATH ahead of system tools — don't undo this.
• The SDK is board-specific: Always cross-compile with the SDK that matches the target.
• The sysroot pkg-configs use prefix=/usr — that's the target /usr, not the host's. $PKG_CONFIG_SYSROOT_DIR rewrites paths automatically.
• Don't try to compile on the board. It has no gcc/g++/pkg-config installed.