gawk: POSIX

 
 A.3 Changes Between SVR4 and POSIX 'awk'
 ========================================
 
 The POSIX Command Language and Utilities standard for 'awk' (1992)
 introduced the following changes into the language:
 
      Options::)
 
    * The use of 'CONVFMT' for controlling the conversion of numbers to
      strings (SeeConversion)
 
    * The concept of a numeric string and tighter comparison rules to go
      with it (SeeTyping and Comparison)
 
    * The use of predefined variables as function parameter names is
      forbidden (SeeDefinition Syntax)
 
    * More complete documentation of many of the previously undocumented
      features of the language
 
    In 2012, a number of extensions that had been commonly available for
 many years were finally added to POSIX. They are:
 
    * The 'fflush()' built-in function for flushing buffered output
      (SeeI/O Functions)
 
    * The 'nextfile' statement (SeeNextfile Statement)
 
    * The ability to delete all of an array at once with 'delete ARRAY'
      (SeeDelete)
 
    SeeCommon Extensions for a list of common extensions not
 permitted by the POSIX standard.
 
    The 2008 POSIX standard can be found online at
 <http://pubs.opengroup.org/onlinepubs/9699919799/>.