string to int

OK last question:

Code:

   		unsigned int j = 0;
		do { 
			if (recv(h,&buf[j],1,0)==SOCKET_ERROR) {
				addlog("retlinehttp(): recv() Failed! %d", WSAGetLastError());
				return -2;
			}
			if (data = strstr(buf, "\r\n\r\n")) {
				data2 = strstr(buf, "Content-Length:");
				data2+=15;
				break;
			}
			//fwrite (&buf[j] , 1 , 1 , file);
			j++;
		} while (j < sizeof(buf));
		buf[j-1]='\0';
		
		int size = atoi(data2);

		char* buffer;
		buffer = new char[size];

   		unsigned int k = 0;
		do { 
			if (recv(h,&buffer[k],1,0)==SOCKET_ERROR) {
				addlog("retlinehttp(): recv() Failed! %d", WSAGetLastError());
				return -2;
			}
			fwrite (&buffer[k] , 1 , 1 , file);
			k++;
		} while (k < sizeof(buffer));

At this point somthing went wrong buffer = new char[size];
Lets say I download a file then I get back the information Content-Length: 24576 this value I have as a char and the pointer data2 points to it. Then I convert the char into int. Now the value is in size. But when I try to create a new buffer, the buffer is not big as size, but has a sizeof 4?
Whats wrong?

sizeof returns the size in bytes of the buffer variable (not the value of the contents of said variable) which is 4 because buffer is a 4-byte pointer variable. What you probably want is to use the value in the variable size again in your loop instead:

Code:

int size = atoi(data2);

char* buffer;
buffer = new char[size];

unsigned int k = 0;
do { 
    if (recv(h,&buffer[k],1,0)==SOCKET_ERROR) {
        addlog("retlinehttp(): recv() Failed! %d", WSAGetLastError());
        return -2;
    }
    fwrite (&buffer[k] , 1 , 1 , file);
    k++;
} while (k < size);

Originally Posted by hk_mp5kpdw

sizeof returns the size in bytes of the buffer variable (not the value of the contents of said variable) which is 4 because buffer is a 4-byte pointer variable. What you probably want is to use the value in the variable size again in your loop instead:

Code:

int size = atoi(data2);

char* buffer;
buffer = new char[size];

unsigned int k = 0;
do { 
    if (recv(h,&buffer[k],1,0)==SOCKET_ERROR) {
        addlog("retlinehttp(): recv() Failed! %d", WSAGetLastError());
        return -2;
    }
    fwrite (&buffer[k] , 1 , 1 , file);
    k++;
} while (k < size);

WUHU works perfect
But I don't understand why this works

} while (j < sizeof(buf));

same as the

} while (k < sizeof(buffer));

Because a char array is different from a pointer.