Thread: corrupted stack?

Hi

I'm a complete C newbie. I do have some experience in Java, though. Anyway, I've been working on a small project in C (mostly for leaning purposes), and it compiles, but when I run it I get an error message. I've been reading around online, but haven't found anything that works in fixing it. Here's the error message and the offending code:

Code:

C:\c_programs\test2>up2.exe
      7 [main] up2 1280 _cygtls::handle_exceptions: Exception: STATUS_ACCESS_VIO
LATION
    831 [main] up2 1280 open_stackdumpfile: Dumping stack trace to up2.exe.stack
dump
 876694 [main] up2 1280 _cygtls::handle_exceptions: Exception: STATUS_ACCESS_VIO
LATION
 898744 [main] up2 1280 _cygtls::handle_exceptions: Error while dumping state (p
robably corrupted stack)

Code:

//up2.c
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>


struct Data{
	int currentAmount;
	int isactive;
};


struct Data* data;
static char buffer[5000];


void updateCurrentAmount(void){
	static char lookFor[] = "amount=";  //this string immediatly preceads the amount
	char* startOfExpression = strstr(buffer, lookFor);
	
	if (startOfExpression == NULL){  //we have problems
		printf("ERROR - Error parsing charpane.php");
		exit(-1);
	}	
	
	char* startOfNumber = startOfExpression + strlen(lookFor);
	data->currentAmount = atoi(strncpy("", startOfNumber, 5));
}



//tests updateCurrentLevel function
int main(){
	strcpy(buffer, "name=fred amount=12345 isactive=1");
	data = (struct Data*) malloc(sizeof(struct Data));
	
	
	updateCurrentAmount();
	
	printf("current level = %i", data->currentAmount);
	return 0;
}

Any help you can give me would be much appriciated. Thank you.

Code:

strncpy("", startOfNumber, 5)

"" should instead be a buffer large enough to hold startOfNumber (5).

Thanks for the help. Such a simple little mistake but I never would have found it.

Thanks again.