commands(3)

NAME

commands - read and obey 0erminated commands

#include <commands.h>

int commands(&ss,c);

substdio ss;
struct commands c[];

commands reads a series of commands from ss and follows the corresponding instructions listed in c.

commands returns 0 when it reaches end of file. It returns -1, setting errno appropriately, if it runs out of
memory or has trouble reading ss.: is removed.
Each command is terminated by 0 ,atheal final lines are ignored. If a command ends with
Each command contains a verb, consisting of zero or more
non-space characters, followed optionally by one or more
spaces and an argument.
Recognized verbs are listed in c. c is an array of one or
more struct commands. Each struct has three components: char *verb; void *action(); and void *flush().
verb points to a -terminated string, interpreted without
regard to case. If the command verb matches this string,
commands calls action(arg), followed by flush() if flush is not the zero pointer. Here arg is a pointer to a: -terminated string containing the argument (with any
inside the argument replaced by 0, or the empty string if there is no argument.
Exception: In the last struct in c, verb is the 0 pointer. commands uses this action for all unrecognized verbs.

The format accepted by commands has been copied from one Internet protocol to another. It is used in SMTP, FTP,
POP, etc.

This does not mean it is a good format. It violates basic
engineering principles. It has produced a continuing
string of interoperability problems.

See http://pobox.com/~djb/proto/design.html for further comments.

If c is initialized to: { { "help", usage, empty }
, { "do", doit, 0 }
, { 0, syntax, empty }
}
and commands receives the input: Do this
undo that
HELP
then commands will call doit("this"), syntax("that"), empty(), usage(""), and empty().