Causes the compiler to produce an assembly whose byte-for-byte output is identical across compilations for identical inputs.




By default, compiler output from a given set of inputs is unique, since the compiler adds a timestamp and a GUID that is generated from random numbers. You use the -deterministic option to produce a deterministic assembly, one whose binary content is identical across compilations as long as the input remains the same.

The compiler considers the following inputs for the purpose of determinism:

  • The sequence of command-line parameters.
  • The contents of the compiler's .rsp response file.
  • The precise version of the compiler used, and its referenced assemblies.
  • The current directory path.
  • The binary contents of all files explicitly passed to the compiler either directly or indirectly, including:
    • Source files
    • Referenced assemblies
    • Referenced modules
    • Resources
    • The strong name key file
    • @ response files
    • Analyzers
    • Rulesets
    • Additional files that may be used by analyzers
  • The current culture (for the language in which diagnostics and exception messages are produced).
  • The default encoding (or the current code page) if the encoding is not specified.
  • The existence, non-existence, and contents of files on the compiler's search paths (specified, for example, by -lib or -recurse).
  • The CLR platform on which the compiler is run.
  • The value of %LIBPATH%, which can affect analyzer dependency loading.

When sources are publicly available, deterministic compilation can be used for establishing whether a binary is compiled from a trusted source. It can also be useful in a continuous build system for determining whether build steps that are dependent on changes to a binary need to be executed.

See also