Memcmp - Revision history

Sandman at 12:46, 29 April 2008

2008-04-29T12:46:56Z

←Older revision		Revision as of 12:46, 29 April 2008
Line 79:		Line 79:
	End		End
	</pre>		</pre>
-	Used in example: [[alloc]](), [[memset]](), [[say]](), [[free]](), [[pointer]]	+	Used in example: [[alloc]](), [[memset]](), [[memcmp]](), [[say]](), [[free]](), [[pointer]]
		+
		+	{{Funcbox
		+	\| category = Memory
		+	}}

Sandman: /* Example */

2007-09-09T23:23:25Z

Example

←Older revision		Revision as of 23:23, 9 September 2007
Line 49:		Line 49:
	memset(pbyte1,3,elements);		memset(pbyte1,3,elements);
	memset(pbyte2,3,elements);		memset(pbyte2,3,elements);
-	result = memcmp(pbyte1,pbyte2,elements); // You can also compare the first 5 bytes, or the first elements/2 bytes,	+	result = memcmp(pbyte1,pbyte2,elements); // You can also compare the first 5 bytes,
-	// it depends on what you want.	+	// or the first elements/2 bytes, it
		+	// depends on what you want.
	say("Memcmp 1: " + result);		say("Memcmp 1: " + result);

Sandman at 11:08, 14 May 2007

2007-05-14T11:08:11Z

←Older revision		Revision as of 11:08, 14 May 2007
Line 6:		Line 6:

	Compares the first ''number'' bytes of the block of memory pointed by ''ptr1'' to the first ''number'' bytes pointed by ''ptr2'', returning zero if they all match or a value different from zero representing which is greater if they do not.		Compares the first ''number'' bytes of the block of memory pointed by ''ptr1'' to the first ''number'' bytes pointed by ''ptr2'', returning zero if they all match or a value different from zero representing which is greater if they do not.
		+
		+	''Available since [[Fenix]] version [[0.92]].''

	== Parameters ==		== Parameters ==

Sandman at 15:13, 13 May 2007

2007-05-13T15:13:32Z

New page

[[Category:functions]]
[[Category:memory]]

==Definition==
'''INT''' memcmp ( <'''VOID POINTER''' ptr1> , <'''VOID POINTER''' ptr2> , <'''INT''' number> )

Compares the first ''number'' bytes of the block of memory pointed by ''ptr1'' to the first ''number'' bytes pointed by ''ptr2'', returning zero if they all match or a value different from zero representing which is greater if they do not.

== Parameters ==
{|
| '''VOID POINTER''' ptr1|| - Pointer to a block of memory
|-
| '''VOID POINTER''' ptr2 || - Pointer to a block of memory.
|-
| '''INT''' number || - The number of bytes to be checked.
|}

== Returns ==
'''INT''' : Difference
{|
| 0 || - The blocks of memory are identical.
|-
| >0 || - The first differing byte in both memory blocks has a greater value in ''ptr1''.
|-
| <0 || - The first differing byte in both memory blocks has a greater value in ''ptr2''.
|}
A byte ranges from 0 to 255, meaning 189 is a greater value than 105.

== Example ==
<pre>
Program example;
Const
elements = 10;
End
Private
byte pointer pbyte1;
byte pointer pbyte2;
int result;
End
Begin

// Allocate memory
pbyte1 = alloc(elements);
pbyte2 = alloc(elements);

// Make the blocks the same and compare
memset(pbyte1,3,elements);
memset(pbyte2,3,elements);
result = memcmp(pbyte1,pbyte2,elements); // You can also compare the first 5 bytes, or the first elements/2 bytes,
// it depends on what you want.
say("Memcmp 1: " + result);

// Make the first block have a greater value and compare
pbyte1[0] = 4;
result = memcmp(pbyte1,pbyte2,elements);
say("Memcmp 2: " + result);

// Make the blocks the same and compare
pbyte2[0] = 4;
result = memcmp(pbyte1,pbyte2,elements);
say("Memcmp 3: " + result);

// Make the first block have a greater value and compare
pbyte2[1] = 5;
result = memcmp(pbyte1,pbyte2,elements);
say("Memcmp 4: " + result);

Repeat
frame;
Until(key(_esc))

// Free the used memory
free(pbyte1);
free(pbyte2);

End
</pre>
Used in example: [[alloc]](), [[memset]](), [[say]](), [[free]](), [[pointer]]