A corresponding C function would be something like Specifically, the movzbl instruction fetches the byte stored at the sum of the two parameters, zero pads it, and stores it into eax. The movsbl instruction takes the lowest byte of eax, sign extends it, and stores the result back in eax.
this works fine. your question was not very clear by the way, so match the layout of your source code with the above.
extern changes the linkage. With the keyword, the function / variable is assumed to be available somewhere else and the resolving is deferred to the linker. There’s a difference between extern on functions and on variables. For variables it doesn’t instantiate the variable itself, i.e. doesn’t allocate any memory. This needs to be done somewhere else. Thus it’s important if … Read more
For both *printf and *scanf, %s expects the corresponding argument to be of type char *, and for scanf, it had better point to a writable buffer (i.e., not a string literal). Using %s in scanf without an explcit field width opens the same buffer overflow exploit that gets did; namely, if there are more characters in the input stream than the target buffer is sized to hold, scanf will … Read more
I see the problem. It’s this line: The == operator has precedence over the = operator. Look at the way you have the parentheses structured on that expression a bit more carefully to see what I mean. sockfd is getting initialize to “0” as a result of being assigned a boolean expression (socket(…) == -1). … Read more
You can’t (usefully) compare strings using != or ==, you need to use strcmp: The reason for this is because != and == will only compare the base addresses of those strings. Not the contents of the strings themselves.
I see the problem. It’s this line: The == operator has precedence over the = operator. Look at the way you have the parentheses structured on that expression a bit more carefully to see what I mean. sockfd is getting initialize to “0” as a result of being assigned a boolean expression (socket(…) == -1). … Read more
Maybe SO_REUSEADDR helps here? http://www.unixguide.net/network/socketfaq/4.5.shtml
Put an l (lowercased letter L) directly before the specifier.
Just put return 0 in your main(). Your function main returns an int (int main(void)) therefore you should add a return in the end of it. Control reaches the end of a non-void function warning: control reaches end of non-void function Solution: This warning is similar to the warning described in Return with no value. If control reaches … Read more