├── Examples.md
└── README.md


/Examples.md:
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 1 | # Fixed Hello World examples
 2 | 
 3 | As mentioned in the [README.md](README.md), many languages do have a way
 4 | to explicitly test for errors on stdout. This file collects examples of
 5 | how to do this in various languages.
 6 | 
 7 | ## C
 8 | 
 9 | ```c
10 | #include <stdio.h>
11 | #include <stdlib.h>
12 | 
13 | int main(void) {
14 |     printf("Hello, World!\n");
15 | 
16 |     if (fflush(stdout) != 0 || ferror(stdout) != 0) {
17 |         return EXIT_FAILURE;
18 |     }
19 | 
20 |     return EXIT_SUCCESS;
21 | }
22 | ```
23 | 
24 | ## C++
25 | 
26 | ```c++
27 | #include <cstdlib>
28 | #include <iostream>
29 | 
30 | int main(int, char**)
31 | {
32 |   std::cout << "Hello World!\n" << std::flush;
33 | 
34 |   return (std::cout.rdstate()) ? EXIT_FAILURE : EXIT_SUCCESS;
35 | }
36 | ```
37 | 
38 | ## Lua
39 | 
40 | ```lua
41 | io.write("Hello World\n")
42 | assert(io:flush())
43 | ```
44 | 
45 | ## Go
46 | 
47 | ```go
48 | package main
49 | 
50 | import "fmt"
51 | 
52 | func main() {
53 | 	if _, err := fmt.Println("Hello, World!"); err != nil {
54 | 		panic(err)
55 | 	}
56 | }
57 | ```
58 | 


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/README.md:
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 1 | # Hello World vs. I/O errors
 2 | 
 3 | In some programming languages, the "Hello, World!" tutorial programs report I/O
 4 | errors in their exit status. In others, they silently swallow I/O errors, which
 5 | doesn't satisfy common expectations of command-line programs.
 6 | 
 7 | Hello world programs are just toy examples. And, most languages do have ways to
 8 | detect I/O errors on standard output. So, this page is effectively about
 9 | defaults and ergonomics, in a specific context.
10 | 
11 | See also [the original blog post] for more discussion.
12 | 
13 | ## Languages with the bug
14 | 
15 | | Language   |  Notes                                     | How to fix the bug
16 | | ---------- | ------------------------------------------ | -----------------------------
17 | | C          | The C standard specifies this behavior     | [Example](Examples.md#C)
18 | | C++        | The C++ standard specifies this behavior   | [Example](Examples.md#C++)
19 | | Crystal    | `Crystal 1.3.2 (2022-01-19)`               |
20 | | Erlang/OTP | [Before Erlang/OTP 26.0](https://github.com/erlang/otp/issues/5797)
21 | | Fortran    | `GNU Fortran 11.2.0`                       |
22 | | Go         | https://news.ycombinator.com/item?id=30612821 | [Example](Examples.md#Go)
23 | | Haxe/HashLink| `Haxe 4.2.4 + HashLink 1.11.0`           |
24 | | Haskell    | `The Glorious Glasgow Haskell Compilation System, version 8.8.4` |
25 | | Java       | This is [documented behavior in Java], [since Java 1.0] |
26 | | Julia      | https://news.ycombinator.com/item?id=30619661 |
27 | | Lua        | `v5.3.3`                                   | [Example](Examples.md#Lua)
28 | | Nim        | `Nim Compiler Version 1.6.4`               |
29 | | Node.js    | `v12.21.0`                                 |
30 | | Pascal     | https://news.ycombinator.com/item?id=30613381 |
31 | | Python 2   | `Python 2.7.18`                            |
32 | | Ruby       | `ruby 2.7.2p137 (2020-10-01 revision 5445e04352) [x86_64-linux-gnu]` |
33 | | Scheme     | `CHICKEN 5.2.0`                            |
34 | | Swift      | `Swift version 5.5.3`                      |
35 | 
36 | ## Languages without the bug
37 | 
38 | | Language   | Notes
39 | | ---------- | ---------------
40 | | Ada        | `GNAT 10.3.0`
41 | | Awk        | `GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)`
42 | | Bash       | `GNU bash, version 5.1.4(1)-release (x86_64-pc-linux-gnu)`
43 | | C#         | `Mono JIT compiler version 6.8.0.105`
44 | | Deno       | `deno 1.11.0 (release, x86_64-unknown-linux-gnu)`
45 | | Erlang/OTP | `Erlang/OTP 26.0` or above
46 | | Hack       | `HHVM 4.108` or above when using [HSL IO]
47 | | Hare       | `hare` + `harec` 20230222 snapshot
48 | | Lisp       | `SBCL 2.1.1`
49 | | OCaml      | `4.08.1`
50 | | Perl       | `perl 5, version 32, subversion 1 (v5.32.1) built for x86_64-linux-gnu-thread-multi (with 46 registered patches...)`
51 | | Perl 6     | `v2020.12`
52 | | Php        | `PHP 8.0.8 (cli) (build: Mar  3 2022 14:51:53) ( NTS )`
53 | | PowerShell | https://twitter.com/perostergaard/status/1501936409547993102
54 | | Python 3   | `Python 3.9.5`
55 | | Racket     | `Racket v7.9 [bc]`
56 | | Rust       | This is [documented behavior in Rust].
57 | | Tcl        | `8.6.11`
58 | | Zig        | https://ziglang.org/documentation/master/#Hello-World
59 | 
60 | The specific source code tested comes from doing simple Web searches for
61 | hello world programs. The intention is to test the programs that are presented
62 | to newcomers, and not programs specifically written to fix this bug.
63 | 
64 | In some cases, only a specific implementation has been tested, and it's not yet
65 | been determined what the actual documented or specified behavior is. In those
66 | cases, I've listed the versions tested, or links to reports.
67 | 
68 | Node.js (and Deno) is listed here as a "Language" because JavaScript itself doesn't have
69 | a builtin concept of standard output, so it takes an embedding like Node.js to
70 | connect JS features to command-line concepts such as standard output.
71 | 
72 | PRs adding more languages, more information about existing languages, updates,
73 | or corrections are welcome!
74 | 
75 | [documented behavior in Java]: https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/io/PrintStream.html
76 | [since Java 1.0]: http://web.mit.edu/java_v1.0.2/www/javadoc/java.io.PrintStream.html#checkError()
77 | [documented behavior in Rust]: https://doc.rust-lang.org/stable/std/macro.println.html#panics
78 | [Wikipedia's list of "Hello, World!" programs]: https://en.wikipedia.org/wiki/%22Hello,_World!%22_program#Examples
79 | [The Hello World Collection]: http://helloworldcollection.de/
80 | [the original blog post]: https://blog.sunfishcode.online/bugs-in-hello-world/
81 | [HSL IO]: https://docs.hhvm.com/hack/getting-started/input-and-output
82 | 


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