• Brother Bill (9/9) Dec 06 ```
• Alexandru Ermicioi (2/11) Dec 06 make sure you flush stdout buffer
• H. S. Teoh (9/21) Dec 06 I.e.:
• Andy Valencia (9/11) Dec 06 Of course, if this is debugging or such output which is
• Peter C (24/33) Dec 07 // A newline will force a flush: write("foo\n"); // appears

Brother Bill <brotherbill mail.com> writes:

```
write("foo"); // writes to the console, but it doesn't display 
yet.
writeln;      // Now it displays, with a new line.
```

How to force writing to the console after ```write("foo");```

I am doing this for a tutorial video, and want the 
```write("foo");```
to immediately write to the console.

Alexandru Ermicioi <alexandru.ermicioi gmail.com> writes:

On Saturday, 6 December 2025 at 21:25:27 UTC, Brother Bill wrote:
 ```
 write("foo"); // writes to the console, but it doesn't display 
 yet.
 writeln;      // Now it displays, with a new line.
 ```

 How to force writing to the console after ```write("foo");```

 I am doing this for a tutorial video, and want the 
 ```write("foo");```
 to immediately write to the console.

make sure you flush stdout buffer

"H. S. Teoh" <hsteoh qfbox.info> writes:

On Sat, Dec 06, 2025 at 11:07:30PM +0000, Alexandru Ermicioi via
Digitalmars-d-learn wrote:
 On Saturday, 6 December 2025 at 21:25:27 UTC, Brother Bill wrote:
 ```
 write("foo"); // writes to the console, but it doesn't display yet.
 writeln;      // Now it displays, with a new line.
 ```
 
 How to force writing to the console after ```write("foo");```
 
 I am doing this for a tutorial video, and want the
 ```write("foo");``` to immediately write to the console.

 
 make sure you flush stdout buffer

I.e.:

```
	write("something");
	stdout.flush;
```


T

-- 
MICROSOFT = Most Intelligent Customers Realize Our Software Only Fools Teenagers

Andy Valencia <dont spam.me> writes:

On Saturday, 6 December 2025 at 23:51:04 UTC, H. S. Teoh wrote:
 	write("something");
 	stdout.flush;

Of course, if this is debugging or such output which is 
orthogonal to the main code's output, stderr is a good choice, as 
it's unbuffered.

```d
import std.stdio : stdout;

stderr.write("Hello, world.");
```

(The output comes immediately with the call.)

Peter C <peterc gmail.com> writes:

On Saturday, 6 December 2025 at 21:25:27 UTC, Brother Bill wrote:
 ```
 write("foo"); // writes to the console, but it doesn't display 
 yet.
 writeln;      // Now it displays, with a new line.
 ```

 How to force writing to the console after ```write("foo");```

 I am doing this for a tutorial video, and want the 
 ```write("foo");```
 to immediately write to the console.

// A newline will force a flush: write("foo\n"); // appears 
immediately

// You could also do it in an 'unsafe' C way, by disabling 
buffering.
// D makes it ever so easy to simply drop into C mode code

// Or make a call to stdout.flush() - as others have noted 
already.

module myModule;
import std.stdio : write;
import core.thread;
import core.stdc.stdio;
 safe:
private:

 trusted void main()
{
     // Disable buffering
     setvbuf(core.stdc.stdio.stdout, null, _IONBF, 0); // NOTE: 
Calls into C are not  safe

     write("foo"); // appears immediately
     Thread.sleep(3.seconds);

     // NOTE: Toggling buffering modes mid-program is unwise ;-)
     // So pick one mode at startup, or use stdout.flush()
}