• Top
  • Documentation
  • Books
    • Cert.pl
      • Cert_param
      • Preliminaries
      • Using-extended-ACL2-images
      • Distributed-builds
      • Certifying-simple-books
      • Pre-certify-book-commands
      • ACL2-system-feature-dependencies
      • Static-makefiles
      • Optimizing-build-time
      • Raw-lisp-and-other-dependencies
      • Custom-certify-book-commands
      • Include-events
      • Ifdef
      • Ifdef-define
      • Ifndef
      • Ifdef-undefine
      • Ifdef-undefine!
      • Ifdef-define!
      • Include-src-events
    • Community-books
    • Project-dir-alist
    • Bookdata
    • Uncertified-books
    • Book-hash
    • Sysfile
    • Show-books
    • Best-practices
    • Books-reference
    • Where-do-i-place-my-book
    • Books-tour
  • Boolean-reasoning
  • Projects
  • Debugging
  • Std
  • Proof-automation
  • Macro-libraries
  • ACL2
  • Interfacing-tools
  • Hardware-verification
  • Software-verification
  • Math
  • Testing-utilities

• Cert.pl

Ifndef

Run some events only if an environment variable is undefined or empty, with build system support.

See ifdef.