Info Catalog gawk: Special Network gawk: Special Files

gawk: Special Caveats

 
 5.8.3 Special File name Caveats
 -------------------------------
 
 Here are some things to bear in mind when using the special file names
 that 'gawk' provides:
 
    * Recognition of the file names for the three standard preopened
      files is disabled only in POSIX mode.
 
    * Recognition of the other special file names is disabled if 'gawk'
      is in compatibility mode (either '--traditional' or '--posix';
      Options).
 
    * 'gawk' _always_ interprets these special file names.  For example,
      using '/dev/fd/4' for output actually writes on file descriptor 4,
      and not on a new file descriptor that is 'dup()'ed from file
      descriptor 4.  Most of the time this does not matter; however, it
      is important to _not_ close any of the files related to file
      descriptors 0, 1, and 2.  Doing so results in unpredictable
      behavior.
 

Info Catalog gawk: Special Network gawk: Special Files