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RWARRAY(3am)               GNU Awk Extension Modules              RWARRAY(3am)

NAME
       writea, reada, writeall, readall - write and read gawk arrays to/from
       files

SYNOPSIS
       @load "rwarray"

       ret = writea(file, array)
       ret = reada(file, array)
       ret = writeall(file)
       ret = readall(file)

DESCRIPTION
       The rwarray extension adds functions named writea(), reada(),
       writeall(), and readall(), as follows.

       writea()
              This function takes a string argument, which is the name of the
              file to which dump the array, and the array itself as the second
              argument.  writea() understands multidimensional arrays.  It
              returns one on success, or zero upon failure.

       reada()
              is the inverse of writea(); it reads the file named as its first
              argument, filling in the array named as the second argument. It
              clears the array first.  Here too, the return value is one on
              success and zero upon failure.

       writeall()
              This function takes a string argument, which is the name of the
              file to which dump the state of all variables. Calling this
              function is completely equivalent to calling writea() with the
              second argument equal to SYMTAB.  It returns one on success, or
              zero upon failure.

       readall()
              This function takes a string argument, which is the name of the
              file from which to read the contents of various global
              variables.  For each variable in the file, the data is loaded
              unless the variable already exists. If the variable already
              exists, the data for that variable in the file is ignored.  It
              returns one on success, or zero upon failure.

NOTES
       The array created by reada() is identical to that written by writea()
       in the sense that the contents are the same. However, due to
       implementation issues, the array traversal order of the recreated array
       will likely be different from that of the original array.  As array
       traversal order in AWK is by default undefined, this is not
       (technically) a problem.  If you need to guarantee a particular
       traversal order, use the array sorting features in gawk to do so.

       The file contains binary data.  All integral values are written in
       network byte order.  However, double precision floating-point values
       are written as native binary data.  Thus, arrays containing only string
       data can theoretically be dumped on systems with one byte order and
       restored on systems with a different one, but this has not been tried.

EXAMPLE
       @load "rwarray"
       ...
       ret = writea("arraydump.bin", array)
       ...
       ret = reada("arraydump.bin", array)
       ...
       ret = writeall("globalstate.bin")
       ...
       ret = readall("globalstate.bin")

SEE ALSO
       GAWK: Effective AWK Programming, filefuncs(3am), fnmatch(3am),
       fork(3am), inplace(3am), ordchr(3am), readdir(3am), readfile(3am),
       revoutput(3am), time(3am).

AUTHOR
       Arnold Robbins, arnold@skeeve.com.

COPYING PERMISSIONS
       Copyright (C) 2012, 2013, 2018, 2022 Free Software Foundation, Inc.

       Permission is granted to make and distribute verbatim copies of this
       manual page provided the copyright notice and this permission notice
       are preserved on all copies.

       Permission is granted to copy and distribute modified versions of this
       manual page under the conditions for verbatim copying, provided that
       the entire resulting derived work is distributed under the terms of a
       permission notice identical to this one.

       Permission is granted to copy and distribute translations of this
       manual page into another language, under the above conditions for
       modified versions, except that this permission notice may be stated in
       a translation approved by the Foundation.

Free Software Foundation          Mar 11 2022                     RWARRAY(3am)