C Tools Last updated Feb 11, 2025

Table of Contents

Linux
MacOS

Linux

MacOS

The static linker (or “link editor”) is ld, the dynamic linker is dyld.

Relevant manpages: ld(1), dyld(1), dyld_info(1) (not dyldinfo);

`xcrun`

“[P]rovides a means to locate or invoke developer tools from the command-line”.

E.g. compare xcrun -find <tool> and which <tool>.

xcrun --show-sdk-path

xcrun --find clang
      Finds the path to the clang binary in the default SDK.

xcrun --sdk macosx --show-sdk-path
      Prints the path to the current Mac OS X SDK.

xcrun --sdk macosx clang test.c
    compile using clang from the macosx sdk

`xcode-select(1)`

`xcodebuild(1)`

xcodebuild -showsdks

Lists all available SDKs that Xcode knows about.

`otool(1)`

“Preferred tool for inspecting Mach-O binaries”

See also llvm-otool(1), objdump(1), etc. “The unambiguous invocation of otool(1) can be found as otool-classic(1) and typically will be run by using the xcrun(1) utility:

% xcrun otool-classic -hv file

-l print the load commands
-L print shared libraries used
-D print shared library id name
-C print linker optimization hints

`install_name_tool(1)`

`libtool(1)`

“The libtool command takes the specified input object files and creates a library for use with the link editor, ld(1).”

“Libtool with -static is intended to replace ar(5) and ranlib.”
“To build a dynamically linked library, libtool, runs the link editor, ld(1), with -dylib once for each architecture present in the input objects and then lipo(1) to create a universal file if needed.”

“To maximize sharing of a dynamically linked shared library the objects should be compiled with the -dynamic flag of cc(1) to produce indirect undefined references and position-independent code.”

`lipo`

“Creates or operates on ``universal'' (multi-architecture) files.”

`vtool`

“Displays and edits build and source version numbers embedded in the Mach-O(5) file format.”

$  vtool -show bazel-bin/src/test.exe
bazel-bin/src/test.exe:
Load command 11
      cmd LC_BUILD_VERSION
  cmdsize 32
 platform MACOS
    minos 14.0
      sdk 14.5
   ntools 1
     tool LD
  version 1053.12
Load command 12
      cmd LC_SOURCE_VERSION
  cmdsize 16
  version 0.0

executable: dynamic libs

To see which dynamic libs are linked into an executable:

export DYLD_PRINT_LIBRARIES=1 export DYLD_PRINT_LIBRARIES_POST_LAUNCH=1 export DYLD_PRINT_RPATHS=1