1RWARRAY(3am) GNU Awk Extension Modules RWARRAY(3am)
2
6 writea, reada, writeall, readall - write and read gawk arrays to/from
7 files
8
10 @load "rwarray"
11 ret = writea(file, array)
13 ret = reada(file, array)
14 ret = writeall(file)
15 ret = readall(file)
16
18 The rwarray extension adds functions named writea(), reada(),
19 writeall(), and readall(), as follows.
20 writea()
22 This function takes a string argument, which is the name of the
23 file to which dump the array, and the array itself as the second
24 argument. writea() understands multidimensional arrays. It re‐
25 turns one on success, or zero upon failure.
26 reada()
28 is the inverse of writea(); it reads the file named as its first
29 argument, filling in the array named as the second argument. It
30 clears the array first. Here too, the return value is one on
31 success and zero upon failure.
32 writeall()
34 This function takes a string argument, which is the name of the
35 file to which dump the state of all variables. Calling this
36 function is completely equivalent to calling writea() with the
37 second argument equal to SYMTAB. It returns one on success, or
38 zero upon failure.
39 readall()
41 This function takes a string argument, which is the name of the
42 file from which to read the contents of various global vari‐
43 ables. For each variable in the file, the data is loaded unless
44 the variable already exists. If the variable already exists, the
45 data for that variable in the file is ignored. It returns one
46 on success, or zero upon failure.
47
49 The array created by reada() is identical to that written by writea()
50 in the sense that the contents are the same. However, due to implemen‐
51 tation issues, the array traversal order of the recreated array will
52 likely be different from that of the original array. As array traver‐
53 sal order in AWK is by default undefined, this is not (technically) a
54 problem. If you need to guarantee a particular traversal order, use
55 the array sorting features in gawk to do so.
56 The file contains binary data. All integral values are written in net‐
58 work byte order. However, double precision floating-point values are
59 written as native binary data. Thus, arrays containing only string
60 data can theoretically be dumped on systems with one byte order and re‐
61 stored on systems with a different one, but this has not been tried.
62
64 @load "rwarray"
65 ...
66 ret = writea("arraydump.bin", array)
67 ...
68 ret = reada("arraydump.bin", array)
69 ...
70 ret = writeall("globalstate.bin")
71 ...
72 ret = readall("globalstate.bin")
73
75 GAWK: Effective AWK Programming, filefuncs(3am), fnmatch(3am),
76 fork(3am), inplace(3am), ordchr(3am), readdir(3am), readfile(3am),
77 revoutput(3am), time(3am).
78
80 Arnold Robbins, arnold@skeeve.com.
81
83 Copyright © 2012, 2013, 2018, 2022 Free Software Foundation, Inc.
84 Permission is granted to make and distribute verbatim copies of this
86 manual page provided the copyright notice and this permission notice
87 are preserved on all copies.
88 Permission is granted to copy and distribute modified versions of this
90 manual page under the conditions for verbatim copying, provided that
91 the entire resulting derived work is distributed under the terms of a
92 permission notice identical to this one.
93 Permission is granted to copy and distribute translations of this man‐
95 ual page into another language, under the above conditions for modified
96 versions, except that this permission notice may be stated in a trans‐
97 lation approved by the Foundation.
98Free Software Foundation Mar 11 2022 RWARRAY(3am)