gawk: Extension Sample Read write array
16.7.9 Dumping and Restoring an Array
-------------------------------------
The 'rwarray' extension adds two functions, named 'writea()' and
'reada()', as follows:
'@load "rwarray"'
This is how you load the extension.
'ret = writea(file, array)'
This function takes a string argument, which is the name of the
file to which to dump the array, and the array itself as the second
argument. 'writea()' understands arrays of arrays. It returns one
on success, or zero upon failure.
'ret = reada(file, array)'
'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, or zero upon failure.
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 re-created array
is likely to be different from that of the original array. As array
traversal order in 'awk' is by default undefined, this is (technically)
not a problem. If you need to guarantee a particular traversal order,
use the array sorting features in 'gawk' to do so (
Array
Sorting).
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.
Here is an example:
@load "rwarray"
...
ret = writea("arraydump.bin", array)
...
ret = reada("arraydump.bin", array)
Info Catalog
gawk: Extension Sample Rev2way
gawk: Extension Samples
gawk: Extension Sample Readfile