Boolean - Revision history

Aoineko at 15:07, 24 March 2024

2024-03-24T15:07:17Z

Aoineko at 00:37, 5 January 2024

2024-01-05T00:37:20Z

Aoineko at 11:52, 4 October 2022

2022-10-04T11:52:29Z

Aoineko at 11:47, 4 October 2022

2022-10-04T11:47:34Z

Aoineko at 11:47, 4 October 2022

2022-10-04T11:47:11Z

Aoineko at 11:33, 4 October 2022

2022-10-04T11:33:37Z

Aoineko: Created page with "In {{MSXGL}}, boolean can be defined using the type `bool`. While booleans are supposed to have only two values (true or false), here we use an 8-bit unsigned integer..."

2022-10-04T11:33:00Z

Created page with "In {{MSXGL}}, boolean can be defined using the type <tt>bool</tt>. While booleans are supposed to have only two values (true or false), here we use an 8-bit unsigned integer..."

New page

In {{MSXGL}}, boolean can be defined using the type <tt>bool</tt>.

While booleans are supposed to have only two values (true or false), here we use an 8-bit unsigned integer to store this value.<br/>
Its value can therefore go from 0 to 255.<br/>
By convention, we use :
* <tt>FALSE</tt> = 0
* <tt>TRUE</tt> = 1 (some engines use <tt>0xFF</tt> value)
⚠️ However, while the value <tt>FALSE</tt> (0) is guaranteed on all boolean function returns, '''the value <tt>TRUE</tt> (1) is never guaranteed''' : Any value other than <tt>FALSE</tt> (0) should be interpret as <tt>TRUE</tt>.<br/>
This choice was made for performance reasons both when returning the value and also when testing the returned value.

How to test that a boolean '<tt>b</tt>' is true:
if(b) // Ok!

if(b != FALSE) // Ok!

if(b == TRUE) // Not Ok! (no guaranteed to work)

← Older revision		Revision as of 15:07, 24 March 2024
Line 23:		Line 23:
	</syntaxhighlight>		</syntaxhighlight>

−	In short, never use <tt>TRUE</tt> to check a boolean value.	+	In short, '''never use <tt>TRUE</tt> to check a boolean value'''.

@@ Line 10: / Line 10: @@
 How to test that a boolean '<tt>b</tt>' is ''true'':
- if(b) // Ok!
+<syntaxhighlight lang="c">
- if(b != FALSE) // Ok!
+if(b) // Ok!
- if(b == TRUE) // Not Ok! (no guaranteed to work)
+if(b != FALSE) // Ok!
 To test that it is ''false'':
- if(!b) // Ok!
+<syntaxhighlight lang="c">
- if(b == FALSE) // Ok!
+if(!b) // Ok!
- if(b != TRUE) // Not Ok! (no guaranteed to work)
+if(b == FALSE) // Ok!
 In short, never use <tt>TRUE</tt> to check a boolean value.

← Older revision		Revision as of 11:52, 4 October 2022
Line 18:		Line 18:
	if(b == FALSE) // Ok!		if(b == FALSE) // Ok!
	if(b != TRUE) // Not Ok! (no guaranteed to work)		if(b != TRUE) // Not Ok! (no guaranteed to work)
		+
		+	In short, never use <tt>TRUE</tt> to check a boolean value.

@@ Line 9: / Line 9: @@
 This choice was made for performance reasons both when returning the value and also when testing the returned value.
- How to test that a boolean '<tt>b</tt>' is ''true'':
+How to test that a boolean '<tt>b</tt>' is ''true'':
   if(b) // Ok!
   if(b != FALSE) // Ok!
   if(b == TRUE) // Not Ok! (no guaranteed to work)
- To test that a boolean '<tt>b</tt>' is ''false'':
+To test that it is ''false'':
   if(!b) // Ok!
   if(b == FALSE) // Ok!
   if(b != TRUE) // Not Ok! (no guaranteed to work)

@@ Line 1: / Line 1: @@
 In {{MSXGL}}, boolean can be defined using the type <tt>bool</tt>.
-While booleans are supposed to have only two values (true or false), here we use an 8-bit unsigned integer to store this value.<br/>
+While booleans are supposed to have only two values (''true'' or ''false''), here we use an 8-bit unsigned integer to store this value.<br/>
 Its value can therefore go from 0 to 255.<br/>
 By convention, we use :
@@ Line 9: / Line 9: @@
 This choice was made for performance reasons both when returning the value and also when testing the returned value.
-How to test that a boolean '<tt>b</tt>' is true:
+ How to test that a boolean '<tt>b</tt>' is ''true'':
   if(b) // Ok!
   if(b != FALSE) // Ok!
   if(b == TRUE) // Not Ok! (no guaranteed to work)

@@ Line 5: / Line 5: @@
 By convention, we use :
 * <tt>FALSE</tt> = 0
-* <tt>TRUE</tt> = 1 (some engines use <tt>0xFF</tt> value)
+* <tt>TRUE</tt> = 1 ''(some engines use <tt>0xFF</tt> value)''
 ⚠️ However, while the value <tt>FALSE</tt> (0) is guaranteed on all boolean function returns, '''the value <tt>TRUE</tt> (1) is never guaranteed''' : Any value other than <tt>FALSE</tt> (0) should be interpret as <tt>TRUE</tt>.<br/>
 This choice was made for performance reasons both when returning the value and also when testing the returned value.

Boolean - Revision history

Aoineko at 15:07, 24 March 2024

Aoineko at 00:37, 5 January 2024

Aoineko at 11:52, 4 October 2022

Aoineko at 11:47, 4 October 2022

Aoineko at 11:47, 4 October 2022

Aoineko at 11:33, 4 October 2022

Aoineko: Created page with "In {{MSXGL}}, boolean can be defined using the type bool. While booleans are supposed to have only two values (true or false), here we use an 8-bit unsigned integer..."

Aoineko: Created page with "In {{MSXGL}}, boolean can be defined using the type `bool`. While booleans are supposed to have only two values (true or false), here we use an 8-bit unsigned integer..."