v4.60 problem with "StrStr" (solved in mP 4.80 bèta)

[Dany]

Hi,
according the help the function "StrStr" should return $FFFF when the search string is not found. In reality the following code makes the function return the value 11 in stead if $FFFF:

Code: Select all

  
var Wrd: word;
    Str: string[10];
...
  Str := '1234567890';
  Wrd := StrStr(Str, '012345'); // Wrd gets the value 11.

while this code gives the correct result:

Code: Select all

var Wrd: word;
    Str: string[10];
...
  Str := '123456789';
  Wrd := StrStr(Str, '012345'); // Wrd gets the value $FFFF

In the first case the source string if "filled" completely (all chars used), in the second case it is not.

Thanks in advance!

[filip]

Hi,

I have tried to reproduce this issue in the mikroPascal PRO for PIC 4.60 but had no success.
Which version of the compiler are you using ?

Regards,
Filip.

[Dany]

Hi,

I have tried to reproduce this issue in the mikroPascal PRO for PIC 4.60 but had no success.
Which version of the compiler are you using ?

Regards,
Filip.

v4.60.

[Dany]

Hi Filip,

At this moment I can not reproduce it either, I do not know why. If the problem pops up again I will try to find out more.
Sorry for the inconvenience!

I did see the problem in the simulator, did not try it in real life.

[Dany]

Hi, I was able to reproduce the problem. Apparently the StrStr function also searches the address space following the string searched in.

The following code shows the phenomenon:

Code: Select all

var Str: string[10]; absolute $50;
    Str2: string[50]; absolute $5B; // placed right after Str1 in memory
...
  Str2 := '01234567890';
  Str := '1234567890';
  Wrd := StrStr(Str, '012345'); // function returns 11 in stead of $FFFF 

Apparently StrStr does not stop the search at the boundaries of Str1. The result returned depends on the value of Str2 also.

[janni]

Indeed, the StrStr function has a flow . In an inner loop it doesn't check if the first string ended.

Slightly simplified example should be easier on the developers:

Code: Select all

var Wrd: word;
    Str1: string[4]; absolute $20;
    Str2: string[4]; absolute $25; // placed right after Str1 in memory

begin
  Str1:='1234';
  Str2:='412';
  Wrd:=StrStr(Str1,Str2);   // function returns 5 instead of $FFFF
...

Apparently the strings library needs a thorough check - it's a third routine with a flow (others being StrCmp - see here, and rTrim - if trimmed string is empty or consists of spaces, then preceeding it memory cell will be erased if it contains 32).

[filip]

Hi,

I have reported these issues to our developers and they will solve it as soon as possible.

I apologize for the inconvenience.

Regards,
Filip.

[Dany]

Issue solved in mP 4.80 bèta, including the "rtrim" issue.

Thanks mE guys! Good work.