Equivalent of PEEK$ statement in O2

[Chris Chancellor]

Hello Charles

In PB they have a PEEK$ statement, what is the equivalent in O2  ?

some people said that PEEK$ work could be done using the Mid()  statement

[Patrice Terrier]

Very easy to write your own, if you know how to work with pointers.
I have plainty of C++ code to emulate the PB string management, most of them are written for 64-bit UNICODE (Windows native).

They could be found in the Tools.h include file, that comes along in all my C++ projects.

The MoveMemory {RtlMoveMemory} API is also the lowest way to manipulate anything. And it works with any language.

[Charles Pegge]

Yes, copying with pointers is a fundamental ability. In o2, peek$ would require 2 steps

1 make a null string to receive the bytes
2 copy the bytes

copy dest, source, count

You can also copy to and from other variable types, such as ints, floats and UDTs. The compiler won't try to prevent you

Code Select Expand


'2018-05-02 T 12:11:03
'peek$
string s="0123456789"
string r=nuls 8
copy strptr(r),strptr(s)+1,8
print r
'
'peek int
string s="0123456789"
int v[2]
copy @v,strptr(s)+1,8
print hex(v[1]) ", " hex(v[2])


[Chris Chancellor]

Thanxx Charles and Patrice

as for the Peek$ , for  the string s="0123456789"

then
      string r=nuls 8

should have been
     string r=nuls 9 
     
bcos  the string length is 9
am i correct?


While for  the peek int , it should be
copy @v,strptr(s)+1,9

instead of
copy @v,strptr(s)+1,8

[Charles Pegge]

The demo was to peek at the middle 8 characters (ignoring 0 and 9).