File: gawk.info,  Node: POSIX,  Next: BTL,  Prev: SVR4,  Up: Language History

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:

   * The use of '-W' for implementation-specific options (*note
     Options::)

   * The use of 'CONVFMT' for controlling the conversion of numbers to
     strings (*note Conversion::)

   * The concept of a numeric string and tighter comparison rules to go
     with it (*note Typing and Comparison::)

   * The use of predefined variables as function parameter names is
     forbidden (*note Definition 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
     (*note I/O Functions::)

   * The 'nextfile' statement (*note Nextfile Statement::)

   * The ability to delete all of an array at once with 'delete ARRAY'
     (*note Delete::)

   *Note Common Extensions:: for a list of common extensions not
permitted by the POSIX standard.

   The 2018 POSIX standard can be found online at
.