chr() and unicode

pdwyer · Post by **pdwyer** » Fri Oct 05, 2007 2:39 pm

How does chr() work with unicode (or doesn't it?)

Syntax

Text$ = Chr(ASCII-Value)
Description

Returns the character associated with the given ASCII value.

Example :
Debug Chr(33) ; Will display "!"

Does the example from the docs become "33,00"? When I use it in the replacestring function in a unicode app is that supported? does it do anything with the zeros?

ASC() seems to work okay but I figure it's easier to ask then write lots of test code to make up for sparse documentation on CHR()

Kaeru Gaman · Post by **Kaeru Gaman** » Fri Oct 05, 2007 2:46 pm

works with 16bit args, if Unicode enabled.

give it a try:

Code: Select all

MessageRequester("unitest", "A:"+Chr($fe)+" U:"+Chr($01fe))

if you Debug the two chars, you'll get two times the first one...

srod · Post by **srod** » Fri Oct 05, 2007 2:48 pm

Yep, all is handled okay :

(Compile with the unicode switch)

Code: Select all

a$ = Chr(65)+Chr(66)
Debug PeekW(@a$)
Debug PeekW(@a$+2)

**EDIT : whop, too slow!

Kaeru Gaman · Post by **Kaeru Gaman** » Fri Oct 05, 2007 2:50 pm

whoo.. this is kind of record to be faster than you, srod...

it was an honor to me.. *bow*

srod · Post by **srod** » Fri Oct 05, 2007 2:55 pm

pdwyer · Post by **pdwyer** » Fri Oct 05, 2007 3:19 pm

so "MyString + chr(0)" adds how many zeros?

one wide one I guess

Trond · Post by **Trond** » Fri Oct 05, 2007 5:28 pm

pdwyer wrote:so "MyString + chr(0)" adds how many zeros?

one wide one I guess

MyString + Chr(0) returns the original string, because strings are zero terminated.

Kaeru Gaman · Post by **Kaeru Gaman** » Fri Oct 05, 2007 5:43 pm

Trond wrote:MyString + Chr(0) returns the original string, because strings are zero terminated.

that's definitely correct...
but he asked how much it adds, not what much it returns...

Chr(Nr) should add two byte in a Unicode exe.

Trond · Post by **Trond** » Fri Oct 05, 2007 6:17 pm

Kaeru Gaman wrote:
Trond wrote:MyString + Chr(0) returns the original string, because strings are zero terminated.
that's definitely correct...
but he asked how much it adds, not what much it returns...

Chr(Nr) should add two byte in a Unicode exe.

No, it will add 0 bytes.
Let's say Chr(0) returns four bytes: 0, 0, 0, 0. The string concatenation function will treat the first two zeros as the string end. And since there is nothing before the string end nothing will get added.

Kaeru Gaman · Post by **Kaeru Gaman** » Fri Oct 05, 2007 6:29 pm

Kaeru Gaman wrote:Chr(Nr) should add two byte in a Unicode exe.

...what exactly is your personal problem with me? :roll:

Trond · Post by **Trond** » Fri Oct 05, 2007 6:42 pm

Kaeru Gaman wrote:
Kaeru Gaman wrote:Chr(Nr) should add two byte in a Unicode exe.
...what exactly is your personal problem with me? :roll:

that's definitely correct...
but he asked how much Chr(0) adds, not how much Chr(Nr) adds.

Kaeru Gaman · Post by **Kaeru Gaman** » Fri Oct 05, 2007 6:46 pm

yes, that's right

I just made a test to be on the sure side... NULLs are not added...
so, the question how much a Zero adds is really nonsense, you got it...

pdwyer · Post by **pdwyer** » Sat Oct 06, 2007 6:03 am

It's nonesense if it adds a wide zero as that will just terminate the string. the docs are vague though and specifically mention ascii so if it only added one byte (not a word) then the string wouldn't terminate in unicode and the string would be one zero byte longer.

In powerbasic I had to add two myself as it didn't have unicode compile.

Trond · Post by **Trond** » Sat Oct 06, 2007 10:07 am

pdwyer wrote:It's nonesense if it adds a wide zero as that will just terminate the string. the docs are vague though and specifically mention ascii so if it only added one byte (not a word) then the string wouldn't terminate in unicode and the string would be one zero byte longer.

In powerbasic I had to add two myself as it didn't have unicode compile.

Let's say Chr() returns just one byte, as you want. It would still have the same effect. Chr(0) would return 0, 0, 0. The string will terminate with the two first null bytes.

pdwyer · Post by **pdwyer** » Sat Oct 06, 2007 11:39 am

Actually I don't want.

I just want to know how it works.

I wonder if you can run the PB chm file with a -v?