behavior of strlen() [modified]

[Rajkumar R]

still, it searches for the '\0' character.

koumodaki wrote:

what value would len have when the above code gets executed?

len = number of character preceeding a '\0' character.

koumodaki wrote:

RegQueryValueEx(hKey, "Mode", 0, NULL, (LPBYTE)my_str, &len);

here it expects the buffer size not the string len.

[koumodaki]

but '\0' is not present. So how does it know the end of the char array? what value gets stored in len?

[Rajkumar R]

i modified my reply please look at it.

[David Crow]

koumodaki wrote:

but '\0' is not present.

It is, just not at the location you desire. For example, if my_str resides at memory address 0x1234, then strlen() will start counting from that locaton until it finds a '\0' character. Use your debugger to see this in action.

"Normal is getting dressed in clothes that you buy for work and driving through traffic in a car that you are still paying for, in order to get to the job you need to pay for the clothes and the car and the house you leave vacant all day so you can afford to live in it." - Ellen Goodman

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

[koumodaki]

my_str is actualy buffer to store the registry key data. Since I am using strlen() to ge the buffer size, I wanted to know the side-effects of using the function this way. Also I have not initilized my_str to any value. As far as I know only memory is alocatd by the compiler when I define the array. So can I safetly assume that the variable len = 6, the size of decalred array?

[David Crow]

koumodaki wrote:

Since I am using strlen() to ge the buffer size...

strlen() dos not get the size of anything. Use sizeof instead.

koumodaki wrote:

...I wanted to know the side-effects of using the function this way.

At a minimum, the program won't work.

koumodaki wrote:

Also I have not initilized my_str to any value.

But it does get initialized, whether you did it or not.

koumodaki wrote:

So can I safetly assume that the variable len = 6, the size of decalred array?

You can, but you'd be wrong.

"Normal is getting dressed in clothes that you buy for work and driving through traffic in a car that you are still paying for, in order to get to the job you need to pay for the clothes and the car and the house you leave vacant all day so you can afford to live in it." - Ellen Goodman

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

[Rajkumar R]

koumodaki wrote:

Since I am using strlen() to ge the buffer size

buffer size and string len cannot interpretted same.

koumodaki wrote:

As far as I know only memory is alocatd by the compiler when I define the array

size of array is the buffer size here.

koumodaki wrote:

So can I safetly assume that the variable len = 6, the size of decalred array?

yes, but if your regvalue string length is greater than 5 you won't get the complete string.

[koumodaki]

Thanks

[koumodaki]

Thanks for explaining

[Chris Losinger]

koumodaki wrote:

I wanted to know the side-effects of using the function this way.

high probability of an Access Violation error, followed by a nasty dialog box and the termination of your application.

image processing toolkits | batch image processing