March 16, 2017

How to check linking and dependencies for libraries and applications.

If you are building (cross platform) applications, its good to know how to check linkage/dependencies of applications and libraries. Here are some simple examples for various operating systems.

Linux – ldd

The ldd command prints the shared objects (shared libraries) required by each program or shared object specified on the command line.

[frank@localhost ~]$ ldd /usr/bin/grep
	linux-vdso.so.1 (0x00007ffc41788000)
	libpcre.so.1 => /lib64/libpcre.so.1 (0x00007f3148061000)
	libc.so.6 => /lib64/libc.so.6 (0x00007f3147c9b000)
	libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f3147a7d000)
	/lib64/ld-linux-x86-64.so.2 (0x0000557e7139c000)

Mac – otool

The otool command displays specified parts of object files or libraries.

[frank@mbp ~]$ otool -L /usr/bin/grep 
/usr/bin/grep:
	/usr/lib/libbz2.1.0.dylib (compatibility version 1.0.0, current version 1.0.5)
	/usr/lib/liblzma.5.dylib (compatibility version 6.0.0, current version 6.3.0)
	/usr/lib/libz.1.dylib (compatibility version 1.0.0, current version 1.2.8)
	/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1238.0.0)

Windows – dumpbin

The dumpbin command is a COFF/PE Dumper. This can be found in a “Developer Command Prompt for VS2015” terminal, for example.

This is an example involving a simple wxWidgets application.

C:\Users\frank\repos\wxwidgets_ex1\build>dumpbin /dependents main.exe
Microsoft (R) COFF/PE Dumper Version 14.00.24215.1
Copyright (C) Microsoft Corporation.  All rights reserved.


Dump of file main.exe

File Type: EXECUTABLE IMAGE

  Image has the following dependencies:

    COMCTL32.dll
    RPCRT4.dll
    KERNEL32.dll
    USER32.dll
    GDI32.dll
    WINSPOOL.DRV
    SHELL32.dll
    ole32.dll
    OLEAUT32.dll
    COMDLG32.dll
    ADVAPI32.dll
    MSVCP140D.dll
    SHLWAPI.dll
    MSIMG32.dll
    VERSION.dll
    VCRUNTIME140D.dll
    ucrtbased.dll

  Summary

        1000 .00cfg
       47000 .data
        1000 .gfids
        7000 .idata
      150000 .rdata
       43000 .reloc
        1000 .rsrc
      414000 .text
        1000 .tls