Installation (“Deployment”)¶

“Prefix”: Where Everything Comes Together ¶

Multiple projects usually are installed at one prefix ⟶ /usr
Subdirectories
- bin/: executables
- lib/ (or lib64): libraries
- include/: header files (usually comes with -dev or -devel distro packages, as do static libraries)
- share/: data files
- (more)
Build parameter: CMAKE_INSTALL_PREFIX (default: /usr/local)

$ cmake -DCMAKE_INSTALL_PREFIX=/tmp/install /home/jfasch/work/jfasch-home/trainings/material/soup/cmake/07-install-basic

Installing Targets ¶

INSTALL(TARGETS hello DESTINATION lib)                 # <--- lands in <prefix>/lib/
INSTALL(TARGETS hello-first DESTINATION bin)           # <--- lands in <prefix>/bin/
INSTALL(TARGETS hello-second DESTINATION bin)          # <--- lands in <prefix>/bin/

Doing The Installation (`make install`)¶

$ cmake -DCMAKE_INSTALL_PREFIX=/tmp/install /home/jfasch/work/jfasch-home/trainings/material/soup/cmake/07-install-basic
$ make
$ make install
...
Install the project...
-- Install configuration: ""
-- Installing: /tmp/install/lib/libhello.a
-- Installing: /tmp/install/bin/hello-first
-- Installing: /tmp/install/bin/hello-second

$ tree /tmp/install/
/tmp/install/
├── bin
│   ├── hello-first
│   └── hello-second
└── lib
    └── libhello.a

And Shared Libraries?¶

$ cmake -DBUILD_SHARED_LIBS=ON -DCMAKE_INSTALL_PREFIX=/tmp/install /home/jfasch/work/jfasch-home/trainings/material/soup/cmake/07-install-basic
$ make
$ make install
...
-- Set runtime path of "/tmp/install/bin/hello-first" to ""    # <--- RUNPATH?
-- Set runtime path of "/tmp/install/bin/hello-second" to ""   # <--- RUNPATH?
...

$ tree /tmp/install/
/tmp/install/
├── bin
│   ├── hello-first
│   └── hello-second
└── lib
    └── libhello.so

Shared Libraries: Installed Vs. Local (`RUNPATH`)¶

NEEDED

$ readelf  --dynamic ./hello-first
 ...
 0x0000000000000001 (NEEDED)             Shared library: [libhello.so]
 ...

⟶ Executable hello-first depends on hello (CMakeLists.txt: TARGET_LINK_LIBRARIES())

Question: where is that external dependency found when program is started?

Answer 1: local (uninstalled) case

$ readelf  --dynamic ./hello-first
 ...
 0x000000000000001d (RUNPATH)            Library runpath: [/home/jfasch/tmp/cmake-demo:]
 ...

Which libraries would be loaded if I ran ./hello-first?¶

$ ldd ./hello-first
        ...
        libhello.so => /home/jfasch/tmp/cmake-demo/libhello.so (0x00007f773aefe000)
        ...

⟶ uninstalled executable runs from the build directory

$ ./hello-first
Hello World

Answer 2: installed case

$ readelf  --dynamic /tmp/install/bin/hello-first
... no RUNPATH ...

$ ldd /tmp/install/bin/hello-first
        ...
        libhello.so.1 => not found
        ...

⟶ installed executable does not run

$ /tmp/install/bin/hello-first
/tmp/install/bin/hello-first: error while loading shared libraries: libhello.so: cannot open shared object file: No such file or directory

Fix: set loader path, e.g.

$ LD_LIBRARY_PATH=/tmp/install/lib /tmp/install/bin/hello-first
Hello World

Shared Libraries: ABI Versions ¶

Set ABI version (SONAME), and make install

SET_PROPERTY(TARGET hello PROPERTY VERSION "1")

SONAME ELF attribute

$ readelf  --dynamic /tmp/install/bin/hello-first
0x0000000000000001 (NEEDED)             Shared library: [libhello.so.1]

SONAME link (done by ldconfig on a live system, after package installation)

$ tree /tmp/install/
/tmp/install/
├── bin
│   ├── hello-first
│   └── hello-second
└── lib
    ├── libhello.so -> libhello.so.1
    └── libhello.so.1

Installation (“Deployment”)¶

“Prefix”: Where Everything Comes Together¶

Installing Targets¶

Doing The Installation (make install)¶