Subj : Re: Segmentation fault when using malloc with threads
To   : comp.programming.threads
From : Karthik007
Date : Sun Feb 27 2005 11:42 am


>your main will start corrupting stack after 10th >connection:
>cliNum is ever increasing, but you only have >space for 10 clients:

Yes, sir what you said is rite this programs supports only 10 clients i
have trimmed the code so the condition is missing.

>  pthread_t  srvThread[10];
>  struct control data[10];
>  int cliNum = 0;
....
>  cliNum++;
>  data[cliNum] = data[0];


>The statement above probably does not do what >you expect.
>All clients receive garbage (uninitialized) data >as their 'control'.


No sir i have no problem with that(i have trimmed the code so you are
unable to see the initilization of data[0] with data) coz i have connected
some clients and it works perfectly and with structure instances you can
assign the data in one instance to the other by just an equality sign
(like s1 = s2). If there is anything different when using array of
structure instances please let me know.


>info = (struct control *)malloc(sizeof(struct control));
>bzero(info, sizeof(struct control));

>Why not simply "info = calloc(1, sizeof(struct control));" ?

Yes, sir i'll defnitely take this into consideration.


>   info = (struct control *) arg;

>A memory leak: you've just allocated info >dynamically, and now you
>threw away that memory and replaced it with the (auto) "&data[cliNum]"
>allocated on the main thread stack.

Yes, sir now i understand the problem. Thanks a lot for your valuable
suggestion. Sir, if i use memcpy() function to copy the data pointed by
arg ("&data[cliNum]") into the memory pointed by "info" then this problem
can be solved i guess. Am i right in this regard ?


Thanking you
Karthik

.