libutil

.TH OPTGET 3 2022-03-06 "libutil" "libutil Programmer's Manual"

.SH NAME

optget \(em parse command line options

.SH SYNOPSYS

#include "optget.h"

.PP

extern const struct opt \fIOPTGET_INIT\fR;

.PP

int \fBoptget\fR(struct opt *\fIopt\fB, char *\fIav\fB[], int \fIflags\fB);

.SH DESCRIPTION

The \fBoptget\fR() function parses command line options. The parameter \fIopt\fR

is a pointer to an opt struct which contains variables related to a parse run.

The parameter \fIav\fR is the argument vertex as passed to \fImain\fR(). The

paramter \fIflags\fR is a set of binary flags that may customise the parse

execution.

.PP

If the first character of \fIopt.str\fR is not a colon character ':', then an

error message will be printed to standard error in the event of an error.

.PP

The \fBoptget\fR() function will return the value of the next option, if one is

found that is either in \fIopt.str\fR or \fIopt.lops\fR for short and long

options respectively. Once all options have been parsed, \fBoptget\fR() will

return -1. If an invalid option is parsed, \fBoptget\fR() will return a question

mark character '?', and if an option is parsed that requires an argument but one

hasnt been specified then \fBoptget\fR() will return a colon character ':'.

.PP

If an option is parsed, \fIopt.ind\fR will contain the option index,

\fIopt.opt\fR will contain the option character if the option is short, or 0

otherwise, \fIopt.lop\fR will contain the option string if the option is long,

or NULL otherwise, \fIopt.arg\fR will contain the option argument if one is

present, or NULL otherwise.

.SH EXAMPLE

.nf

static struct lop lops[] = {

	{ "help",    ARG_NUL, 256 },

	{ "version", ARG_NUL, 257 },

	{ NULL, 0, 0 }

};

int main(int ac, char *av[]) { A0 = av[0];

	struct opt opt = OPTGET_INIT; opt.str = "ab"; opt.lops = lops;

	for (int o; (o = optget(&opt, av, 1)) != -1;) switch (o) {

	case 'a': { printf("'-a' parsed\\n"); break; }

	case 'b': { printf("'-b' parsed\\n"); break; }

	case 256: { hlp(); return 0; }

	case 257: { ver(); return 0; }

	default: { return 1; }

	} return 0;

}

.fi

.SH COPYRIGHT

.nf

Copyright (C) 2020, Jakob Wakeling

MIT Licence (https://opensource.org/licenses/MIT)

.fi