Re: corrupted pointer when initing a dll

jc <>
30 Apr 2007 13:42:22 -0700
the corresponding code is

int CCCP::StartLoadA2lThread(void){
    function ccp thread
    parameters: void
    //CParseWaitDialog *p_pwd;
    DWORD dParseThreadID;
    m_pWD = DisplayParseWaitDialog();
    m_bA2lLoadThreadActive = TRUE;
    m_hA2lLoadThread = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)
ParseA2lThread, this, 0,&dParseThreadID);
        sGmsg.StringCopy("parsing a2l file thread started");
        sGmsg.StringCopy("a2l parse thread not started");
    return 1;

void CCCP::ParseA2lThread(LPVOID p){
    CCCP *w = (CCCP *)p;
int CCCP::LoadA2LDatabase(jcStr *fname){
    then call parser to parse the a2l file and load all the channel
values, if the parser returns with no error
    return result of the load and parse.
    zero is returned if no error in loading and parsing the a2l file
    int retval;

    InitParser();//this will init the parser objects
    char *temp;
    //fname = m_strA2Lfname;
    temp = fname->ReturnStr();
    retval = Parser(temp, m_bA2lParseTalkative);
    AnalyzeParseError(retval, fname, m_pWD);
    return retval;
On Apr 30, 2:31 pm, "Alexander Nickolov" <> wrote:

Make sure you are not passing pointers on your stack for your
thread to use. Always allocate on the heap data you are to send
to a different thread. Note this is just an educated guess as it's
hard to tell what your problem is with no code posted...

Alexander Nickolov
Microsoft MVP [VC], MCSD

"jc" <> wrote in message

On Apr 30, 9:32 am, dasjotre <> wrote:

On 30 Apr, 14:23, jc <> wrote:

i'm developing a project using vc++.
the main exe is a win32 application. it needs two dlls. one is my own
implementation of string operations. the other dll is to parse a2l
files(it is similar to xml files, but it is based on asap2 standard).
i created the parser using bison and flex. then ported the code to vc+
+ environment including the files lex.yy.c(output from the flex
scanner) from bison) for post processing the
parser output and creating the data structure. the result is a dll
file that i link with my application.

all was well till i realized that this post processing the parser
output(while the parser can finish parsing the file in less than a
minute for a typical a2l file will be around 150,000 lines) takes
around 10 minutes, during the entire application freezes. so i decided
to call the parsing using a separate thread.

i call the parser with the file name. before i call the parser
function i initialize the parser manually.

i reach the parser application in two different paths. in one path
there is a conf file, which has the info about the a2l file and from
there it calls the parser application. this goes well with no problem.

but if i try to load the a2l file directly then the filename pointer
gets corrupted. in different ways
sometimes when i enter the thread
sometimes when i initialize the dll
sometimes when i parse the file

but nothing happens when i call the a2l parse and process thread after
i load the conf file.

i spent a week trying to figure this out and realized that this is
beyond me.
any help and pointer will be appreciated

this is W32 not C++ problem

are you starting that thread inside DLLMain?

Hide quoted text -

- Show quoted text -

no i start the thread inside my application and call the dll functions
from the thread.
i don't think i have anything like dllMain.
there are three functions that i use
0. start the thread (sometimes this file name pointer corrupts here)
1. initparser (this initialises the classes that parse, this is very
useful for me because, this will let me reparse a different file
without closing the application)(it corrupts here too)
2. parser(file name)(if it escaped before, now it is sure that it gets
3. postprocess
4. copythe datastructure from the dll to the application(here i
duplicate all the strucutre, as it will be deleted soon, but these
data structure i need for the application)
4. deleteparser(delete all the memory that i allocated)


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