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Problems with realloc function
andy320
Member
05-19-2004 04:08 AM
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Hello,
I am dynamically building an array of strings. I have defined a pointer to pointer of char (char** MyPointer). To build the array I'm using the realloc-function for both dimensions of the array. This all works well until I want to "delete" the array for a new sequence. For this, I posted the following command:
MyPointer = realloc (MyPointer, 0);
The pointer is set to NULL after this. Now, I want to build the array again and this does not work! I'm not able to allocate more than one char* for the char** MyPointer. I also tried to free the char**, then use malloc and realloc, this doesn't work as well.
I have attached the functions that I'm using to build, rebuild and delete the array.
I am dynamically building an array of strings. I have defined a pointer to pointer of char (char** MyPointer). To build the array I'm using the realloc-function for both dimensions of the array. This all works well until I want to "delete" the array for a new sequence. For this, I posted the following command:
MyPointer = realloc (MyPointer, 0);
The pointer is set to NULL after this. Now, I want to build the array again and this does not work! I'm not able to allocate more than one char* for the char** MyPointer. I also tried to free the char**, then use malloc and realloc, this doesn't work as well.
I have attached the functions that I'm using to build, rebuild and delete the array.
Evrem_Y
NI Employee (retired)
05-24-2004 03:01 AM
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Hi,
I would like to post you a link to a KB, which explains the dynamically allocation of arrays.
http://digital.ni.com/public.nsf/websearch/119E4AA17E0A6F9C86256C4E00568121?OpenDocument
Please let me know if you still have problems.
Evrem Yarkin
Application Engineer
I would like to post you a link to a KB, which explains the dynamically allocation of arrays.
http://digital.ni.com/public.nsf/websearch/119E4AA17E0A6F9C86256C4E00568121?OpenDocument
Please let me know if you still have problems.
Evrem Yarkin
Application Engineer
05-24-2004 05:04 AM
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Hello,
Please read my request and my example.c File again, it's not the problem that I don't know how to allocate memory dynamicly. I found out, that perhaps the variables windows has a bug. When dynamicly allocating memory to a variable and writing content into it, the variables-window is not always updated.
So I can't trust what I see in the variables windows, cause it's not in each case the same that is effectivly stored in memory.
Please read my request and my example.c File again, it's not the problem that I don't know how to allocate memory dynamicly. I found out, that perhaps the variables windows has a bug. When dynamicly allocating memory to a variable and writing content into it, the variables-window is not always updated.
So I can't trust what I see in the variables windows, cause it's not in each case the same that is effectivly stored in memory.
Evrem_Y
NI Employee (retired)
05-25-2004 02:19 AM
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Hi,
I posted the link because normally we do not have any problems with that. Please provide a simple source code file, which i can run without having to declare a lot of variables and describe on which line the variable window misbehaves and what your expectations are.
Evrem Yarkin
I posted the link because normally we do not have any problems with that. Please provide a simple source code file, which i can run without having to declare a lot of variables and describe on which line the variable window misbehaves and what your expectations are.
Evrem Yarkin
05-25-2004 03:14 AM
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Hello,
I now made a simple code file which you can debug. Watch the variable "StepLBDetail" in the variables window. Please open up the StepLBDetail** variable after the first command (Line11) . You can see a char* with the text "Hello world". After the second command the Variables window is not updated before you close and open the StepLBDetail** variable again.
After the "StepLBDelete" command the Variables window only shows one char* after several times adding text with the "StepLBAdd" Command. It is no more updated.
I now made a simple code file which you can debug. Watch the variable "StepLBDetail" in the variables window. Please open up the StepLBDetail** variable after the first command (Line11) . You can see a char* with the text "Hello world". After the second command the Variables window is not updated before you close and open the StepLBDetail** variable again.
After the "StepLBDelete" command the Variables window only shows one char* after several times adding text with the "StepLBAdd" Command. It is no more updated.
