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, and the man pages for the other
extensions shipped with gawk.

AUTHOR

Arnold Robbins, arnold@skeeve.com.

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