CODEWITHSUNDEEP
csegmentation-fault
Anatoly
Anatoly

Reputation: 87

Segmentation Fault SigSegv in simple code C

I have an error "Segmentation Fault SigSegv" in my C code:

int main(void)
{
    HANDLE h;

    char *query = malloc(10);

    h=InitPort("\\\\.\\COM2",57600);
    query = 0;
    query=getenv("QUERY_STRING");


    if (h==INVALID_HANDLE_VALUE)
    {

        printf("Error\n");


        return 0;
    }

    if (strstr(query,"COMM=W")!=0)
    {
        SendData(h,'W');
    }

    return 0;
}

I read a lot of opinions about allocate memory and finally use malloc() function, but it didn't work.

All functions in my code:

HANDLE InitPort(char* PORT,unsigned long BAUD_RATE)
{
  HANDLE h;
  DCB d;
  h=CreateFileA(PORT,GENERIC_READ | GENERIC_WRITE,0,0,OPEN_EXISTING,0, 0);
  GetCommState(h,&d);
  d.BaudRate=BAUD_RATE;
  d.fBinary=1;
  d.fParity=0;
  d.ByteSize=8;
  d.StopBits=ONESTOPBIT;
  SetCommState(h,&d);
  return h;
}

void SendData(HANDLE h,unsigned char byte)
{
  unsigned long n;
  WriteFile(h,&byte,1,&n,NULL);
}

And *char query; query=(char)malloc(sizeof(char)10); didn't work too

Upvotes: 0

Views: 219

Answers (1)

user2600366
user2600366

Reputation: 68

Well, you didnt add your other functions beside main, so I can't figer out the entire picture.

basicly, Segmantation fault casued by refrencing memory that already freed or using pointers in a wrong way.

The usage of malloc may be like this: char s; s=(char)malloc(sizeof(char)*size);

You don't really have to make the casting, but its not a problem.

Upvotes: 0

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