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Tradone

[Answered]Runtime Error. What is instance of 'std::logic_error'

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Is anybody familiar with this error?
terminate called after throwing an instance of 'std::logic_error'
  what():  basic_string::_S_construct NULL not valid
Abort (core dumped)


I yahooed and googled them but apparently, no information was available. [Edited by - Tradone on April 3, 2006 10:07:20 PM]

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That is one of the standard exception classes. You are constructing an std::string with a null character pointer. Can you post your code?


jfl.

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it's about 25 files all together. urm... do I have to still post it?

can you give me an example of what might have been done?
and where can I get information on standard runtime errors like those?
i searched them in the engines and i got no matches. :(

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okay, i fixed it

Error:

Function Parameter::GetData(){
long count = 0;
inputData = "";
char ch;

while (count < envVars.contentLength){
cin.get(ch);
inputData += ch;
count++;
}

if (inputData == "" )
return Failure;

return Success;
}




No Error:


Function Parameter::GetData(){
long count = 0;
inputData = "";
char ch;

while (count < envVars.contentLength){
cin.get(ch);
inputData += ch;
count++;
}

return Success;
}




Difference:

if (inputData == "" )
return Failure;



Thanks!
and if you can just leave me a reference site for the runtime errors.

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If you still want to check if it's a failure, simply check the string's length (>0).
Now, is the compiler assuming that "" is NULL? I thought it would be considered as {'\0'} or something like that...

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Quote:
Original post by deadimp
If you still want to check if it's a failure, simply check the string's length (>0).


Well, we don't even know what inputData, Success, Failure or Function are, so it's hard to pinpoint what he may be doing wrong.

Quote:
Now, is the compiler assuming that "" is NULL?


No.

Quote:
I thought it would be considered as {'\0'} or something like that...


Yes.

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Sorry, but I'm still not getting it. How does that conditional have anything to do with NULL character array initialization?
(My brain left after school)

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Function Parameter::GetData(){
long count = 0;
inputData = "";
char ch;

while (count < envVars.contentLength){
cin.get(ch);
inputData += ch;
count++;
}

if (inputData == "" )
return Failure;

return Success;
}

Function Parameter::SetParameter(){
string s;

if (!GetData())
return Failure;

s = inputData + "&";



[lol]
Seems like I left you guys all puzzled for not showing the whole thing.
okay. here it is.

So the I found out that Parameter::SetParameter() was the method with fault.

Thus, by adding

if (inputData == "" )
return Failure;


I don't have to execute this code.

s = inputData + "&";


and inputData is a private member variable of the class Parameter.

So since inputData = ""
I am trying to do
s = "" + "&"

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[edit] Whoops, that's not right...
I think I need to add that the error message is a little misleading:
Quote:
libstdc++
if (__builtin_expect(__is_null_pointer(__beg) && __beg != __end, 0))
  __throw_logic_error(__N("basic_string::_S_construct NULL not valid"));
So it will complain about NULL even if the char array is just empty ("\0").


Glad you fixed the problem.


jfl.

[Edited by - jflanglois on April 4, 2006 9:44:21 AM]

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oops my bad that wasn't the problem.
the real problem that was causing the thing was this:

getenv("QUERY_STRING")

so if there is no query string passed through the cgi, the returns a NULL.
Before:

if ( s == "&" ){
if ( !ParseGet( getenv("QUERY_STRING") ) )
return Failure;
}


After:

if ( s == "&" && getenv("QUERY_STRING") != NULL ){
if ( !ParseGet( getenv("QUERY_STRING") ) )
return Failure;
}


Difference:
getenv("QUERY_STRING") != NULL


So yea. That was the REAL reason.

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