If you already have installed your favorite NDK somewhere, all you have to do is to export and set NDK_VERSION and ANDROID_NDK_ROOT environment variables, e.g:

export NDK_VERSION=android-ndk-r23b
export ANDROID_NDK_ROOT=$HOME/${NDK_VERSION}

Important: ANDROID_NDK_ROOT must be an absolute path !

If you specify only NDK_VERSION, ANDROID_NDK_ROOT will be automatically set to its default:

export ANDROID_NDK_ROOT=/tmp/${NDK_VERSION}

To specify the minimum SDK version set the environment variable below:

export MIN_SDK_VERSION=21   # Default value if unset

To specify the build directory set the environment variable below:

export ANDROID_BUILD_DIR=${HOME}/android_build

Important: ANDROID_BUILD_ROOT must be an absolute path !

All libraries will be generated under:

${ANDROID_BUILD_DIR}/prefix/<arch>/lib

where <arch> is one of arm, arm64, x86 or x86_64.

You can also check configuration variables in build.sh itself, in its "Configuration & tuning options" comment block.

The variable CURVE accepts 3 different values:

""          : LIBZMQ is built without any encryption support.
"libsodium" : LIBZMQ is built with LIBSODIUM encryption support (see below).
"tweetnacl" : LIBZMQ is build with embedded encryption support.

LIBSODIUM

LIBSODIUM is built along with LIBZMQ, when CURVE="libsodium".

If you have your own clone of LIBSODIUM, set LIBSODIUM_ROOT to point to its folder.
If the variable LIBSODIUM_ROOT is not set, LIBZMQ will look for a folder 'libsodium' close to his own one.
If no folder 'libsodium' exists, then LIBZMQ will clone LIBSODIUM from its official STABLE branch.

Build

See chapter Configuration for configuration options and other details.

Select your prefered parameters:

export XXX=xxx
export YYY=yyy
...

And, in the android directory, run:

./build.sh [ arm | arm64 | x86 | x86_64 ]

Parameter selection and the calls to build.sh can be located in a SHELL script, like in ci_build.sh.

Dockerfile

An example of Docker file is provided, for Ubuntu 22.04

Minimal changes are required to support Debian 9 to 11.

Minimal changes are required to support CentOS (7 only), Rocky Linux (8 & 9), and many Fedora (22 to 37).