On multiple occasions I have wanted to create a command-line interface with different subcommands. Recently I have been experimenting with writing an IRC bot that handles different commands passed to it.
I used the following to create an array of IRC commands (called "handlers") that contains the command that needs to be matched on and the function to call.
struct {
char *cmd;
void (*fn)(struct irc_message *);
} handlers[] = {
{ "001", handle_001 },
{ "PING", handle_ping },
};
Once a command is received we can find the right function to call in the following manner:
struct irc_message *msg = …;
unsigned i;
for (i = 0; i < sizeof(handlers) / sizeof(*handlers); ++i) {
if (strcmp(command, handlers[i].cmd) == 0) {
handlers[i].fn(msg);
break;
}
}
Aside: if you don't like strcmp(), there's strncmp() that can be called as with strlen(command) as the third argument.