在c中使用正则表达式用于strcmp函数

Question

So, what im interesting in trying to do is read in a line with getline and look for specific phases if i see something like "verbose on" or "verbose off" i know what i want to do, however if it is "verbose "something"" then i want to error. Im pretty sure that this is going to require regular expressions because what comes after is arbitrary. Some insight on this problem would be much appreciated. Thank you.

strcmp(buf,"verbose on")==0
strcmp(buf,"verbose off")==0
strcmp(buf,"verbose "regex expression here im thinking"")==0

This is how i think it should go, just need a bit of a push.

Answer 1

No need for a regex. You can use strncmp :

strncmp(buf, "verbose", strlen("verbose")) == 0

This only compares the first 7 characters, so it will match any buf that starts with "verbose".

Note : I'm allergic against magic numbers, but you could of course replace the strlen call with a literal 7 if you prefer. Also, for real code, I would replace the duplicated string literal with a constant.