Using PJSIP in CMake Projects 

After cmake --install has placed PJSIP under a prefix (see Build Instructions with CMake), a downstream CMake project can consume it with a standard find_package call. This page covers the installed package layout, the exported targets, and a minimal working example.

Minimal Example 

Assuming PJSIP was installed under /usr/local (or the prefix is on CMAKE_PREFIX_PATH):

cmake_minimum_required(VERSION 3.28)
project(myapp C)

find_package(Pj REQUIRED)

add_executable(myapp myapp.c)
target_link_libraries(myapp PRIVATE Pj::pjsua-lib)

myapp.c:

#include <pjsua-lib/pjsua.h>
#include <pj/log.h>

int main(void)
{
    pjsua_create();
    PJ_LOG(3, ("myapp.c", "Hello PJSIP! Bye PJSIP."));
    pjsua_destroy();
    return 0;
}

Configure and build:

$ cmake -S . -B build -DCMAKE_PREFIX_PATH=/usr/local
$ cmake --build build -j

find_package(Pj) transitively pulls in everything PJSIP was linked against at install time (OpenSSL, SDL2, FFMPEG, ALSA, and so on). No additional find_package calls are required in the consumer project unless the application itself uses those libraries directly.

Exported Targets 

All PJSIP libraries are exported under the Pj:: namespace. The targets mirror the library layout described in Overview:

Target	What it is
`Pj::pjlib`	Base framework: OS abstraction, data structures, pool allocator.
`Pj::pjlib-util`	Utilities: DNS, STUN, XML, JSON, WebSocket.
`Pj::pjnath`	NAT traversal: STUN, TURN, ICE.
`Pj::pjmedia`	Core media framework: transports, streams, ports, sessions.
`Pj::pjmedia-codec`	Codec implementations and the codec manager.
`Pj::pjmedia-audiodev`	Audio device abstraction (ALSA, Core Audio, WASAPI, Oboe, …).
`Pj::pjmedia-videodev`	Video device abstraction (V4L2, AVFoundation, DirectShow, …).
`Pj::pjsip`	SIP core: transactions, transport, parsing.
`Pj::pjsip-simple`	SIP event/presence (SIMPLE) package.
`Pj::pjsip-ua`	SIP UA layer: dialogs, calls, INVITE/REFER sessions.
`Pj::pjsua-lib`	High-level PJSUA C API (the library most applications link).
`Pj::pjsua2`	PJSUA2 C++ API.

There is also one infrastructure target you normally do not link directly:

Pj::pjlib-ssl – an INTERFACE target that carries the selected SSL backend’s compile and link flags. It is pulled in automatically by any target that needs SSL.

The pjsua command-line application is installed as an executable (<prefix>/bin/pjsua); it is not a library and should not be linked into downstream code.

Selecting Components 

Most applications only need Pj::pjsua-lib or Pj::pjsua2; the other targets are brought in transitively. When you want a narrower link set – for example, a tool that only does SIP parsing without a full UA – link against the specific targets:

target_link_libraries(sip_tool PRIVATE Pj::pjsip Pj::pjlib-util Pj::pjlib)

CMake resolves the transitive dependencies between PJSIP libraries automatically.

Pointing CMake at the Install Prefix 

If PJSIP is installed outside the default search path, tell the consumer project where to look via one of:

$ cmake -S . -B build -DCMAKE_PREFIX_PATH=/opt/pjsip

$ export CMAKE_PREFIX_PATH=/opt/pjsip
$ cmake -S . -B build

$ cmake -S . -B build -DPj_DIR=/opt/pjsip/lib/cmake/Pj

Pj_DIR is the most explicit form and bypasses the rest of CMake’s search logic.

Version Requirements 

find_package(Pj) supports the usual CMake version request:

find_package(Pj 2.17 REQUIRED)

The package is configured with COMPATIBILITY SameMajorVersion, so a request for 2.16 is satisfied by any installed 2.x release (x ≥ 16) but not by a future 3.x.

Embedding PJSIP via `add_subdirectory`

PJSIP can also be embedded into a super-project without a separate install step:

cmake_minimum_required(VERSION 3.28)
project(super C CXX)

set(PJ_SKIP_EXPERIMENTAL_NOTICE ON)
add_subdirectory(third_party/pjproject EXCLUDE_FROM_ALL)

add_executable(myapp myapp.c)
target_link_libraries(myapp PRIVATE pjsua-lib)

In this mode the targets exist without the Pj:: namespace prefix (CMake’s ALIAS mechanism is set up by the export step, which is only run on install). Use the bare target names — pjsua-lib, pjsua2, pjsip, and so on — when linking.

The same PJ_DEP_* and PJMEDIA_WITH_* options can be set in the super-project’s cache before add_subdirectory() to control the embedded build.

Interaction with System Dependencies 

When PJSIP was built with PJ_DEP_<NAME>=system (for example, -DPJ_DEP_SRTP=system), the installed PjConfig.cmake records this choice and calls find_dependency() on the same system packages when you run find_package(Pj). You do not need to call find_package(libsrtp) yourself; it is handled by the config module.

For SSL, the backend chosen at build time is also recorded, so consumers that call find_package(Pj) automatically get the right OpenSSL / GnuTLS / MbedTLS dependency pulled in.