Initializing structure with pointers to char arrays - bug

Vaclav_

Could someone please help me to find my bug.
This is C++ code "running" on Arduino.
It compiles and runs ,but...
I am using a struct to define / collect data which belong together.
The bug is when I enter a character array (using pointer) into the structure variable, also a character array.
The actual variable I am having problem with is ctextPrompts. I am sure there will be more, but this is the first bug.
It is entered properly - verified by test code immediately after - see TOK here note.
However, when I initialize next member of the struture cTextEntry - it wipes out the ctextPrompts.
Initializing next structure member ctextEmulate puts ctextEmulate characters into ctextPrompts.

This is my first attempt to utilize pointers and structure and I MUST have done something really stupid to cause this bug.

I am using LCD to debug the code.

Since the rest of the code works as expected I am pretty sure it is not a "memory" issue, I do verify the size of available RAM on initialization.
I doubt it is a Arduino compiler issue, just plain wrong usage of pointers which I just do not see.

I do apologize for the long code, but I feel it would help to see the debbuging attempts I have made so far.

Thanks for your help.
Cheers
Vaclav

PS While testing I am using both pointer (*) and indexing [0] with same results

char *ctextEntry[] ={ " ", " "," " }; // emulating data char *ctextEmulate[] = { // emulate entries "14260123 ", // start frequency "14360000 ", // end frequency "10000 ", // step frequency "1 ", // step speed "1 ", // 0 single shot 1 repeat "Option" // }; // temporary not completed char *ctextPrompts[] ={ "Start frequency ","End frequency ","Step frequency ","Step speed ","Single / Repeat","Optional "}; typedef struct DataRecordTAG { char *cPrompts[]; // prompt text char *cEmulate[]; // emulate input char *cEntry[]; // response char cTEST; int iIndex; } DataRecord; DataRecord Record[DATA_STRUCT]; // variable int igRecordIndex = 0; // global access to records ....... void InitializeRecords(void) { // changed to global igRecordIndex igRecordIndex // igRecordIndex // initialize prompts and some test entries int iPromptIndex = 0; for

CPallini

Quote:

*Record[igRecordIndex].cPrompts = ctextPrompts[igRecordIndex];

What are you doing with this line?

THESE PEOPLE REALLY BOTHER ME!! How can they know what you should do without knowing what you want done?!?! -- C++ FQA Lite

ahmad_ali

There maybe be several bugs, but I believe you should remove the []:

ypedef struct DataRecordTAG
{
char *cPrompts; // prompt text
char *cEmulate; // emulate input
char *cEntry; // response
char cTEST;
int iIndex;
}

Vaclav_

Initializing the struct member cPrompts (char array) from ctextPrompts (char array). According to next verification code it works. But than things go crazy as described.

Vaclav_

I think what I am doing is assigning pointers in the structure to point to an array. Is that legal / right? Or do I need to physically copy the array to the structure? That will probably wipe out the memory for good. I am sure lost in this . Maybe I need to not use the structure at all.

Vaclav_

Now that does not "copy" the entire array into the structure. But I think I need to work on making the structure pointer equal the array pointer.

Vaclav_

I did remove the array and so far it is working. But I need to check the rest of the code . Thanks Vaclav So basically if read my code in English = assigning a char pointer to point to pointer to array of characters. What I did was wrongly assign a char array pointer to point to array of characters. Thanks to both of you guys to nudge me the correct this. Vaclav

Raushank03

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