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 re-
turns 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 func-
tion 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 suc-
cess, 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 sort-
ing features in gawk to do so.
The file contains binary data. All integral values are written in net-
work 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
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approved by the Foundation.
Free Software Foundation Mar 11 2022 RWARRAY(3am)
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