args.h: Parser Helpers

Overview

Parser callback generation and built-in parser helpers.

Built-in parser wrappers

ARG_PARSE_L, ARG_PARSE_LL, ARG_PARSE_UL, ARG_PARSE_ULL, ARG_PARSE_F, and ARG_PARSE_D are convenience wrappers around ARG_PARSER.

Custom parser contract

Custom parser callbacks return ARG_INVALID or ARG_VALID and use signature (const char *str, void *dest).

Parser Generation
#define	ARG_PARSER(name, strto, ARG_BASE, strto_t, dest_t, CAST, cond, err)
	Generates a typed parser callback with common conversion checks.
#define	ARG_BASE(N)
	Helper for the ARG_BASE parameter in ARG_PARSER.
#define	ARG_ERR   "Invalid value"
	Default parser error message if err is empty in ARG_PARSER.
#define	ARG_INVALID(msg)
	Creates a failing arg_callback value.
#define	ARG_VALID()
	Creates a successful arg_callback value.

Built-in Parser Wrappers
#define	ARG_PARSE_L(name, base, dest_t, CAST, cond, err)
	Convenience wrapper of ARG_PARSER using strtol.
#define	ARG_PARSE_LL(name, base, dest_t, CAST, cond, err)
	Convenience wrapper of ARG_PARSER using strtoll.
#define	ARG_PARSE_UL(name, base, dest_t, CAST, cond, err)
	Convenience wrapper of ARG_PARSER using strtoul.
#define	ARG_PARSE_ULL(name, base, dest_t, CAST, cond, err)
	Convenience wrapper of ARG_PARSER using strtoull.
#define	ARG_PARSE_F(name, dest_t, CAST, cond, err)
	Convenience wrapper of ARG_PARSER using strtof.
#define	ARG_PARSE_D(name, dest_t, CAST, cond, err)
	Convenience wrapper of ARG_PARSER using strtod.

Data Structures
struct	args_raw
	Copy of the raw process argument vector. More...

Macro Definition Documentation

ARG_PARSER

#define ARG_PARSER	(		name,
			strto,
			ARG_BASE,
			strto_t,
			dest_t,
			CAST,
			cond,
			err )

Generates a typed parser callback with common conversion checks.

The generated function is named parse_<name> and matches argument::parse_callback. It parses str, rejects malformed input, range errors, and custom condition failures, then writes to dest.

Parameters

name	Suffix used for generated function name.
strto	Conversion routine, e.g. strtol or strtod.
ARG_BASE	Macro, leave out macro for no base, or e.g. ARG_BASE(10) to pass to strto.
strto_t	Return type of strto.
dest_t	Destination pointee type.
CAST	Optional cast expression when narrowing/widening.
cond	Rejection predicate evaluated against local variable val.
err	Error text, falls back to ARG_ERR when empty.

Return values

ARG_VALID	Input accepted and stored in dest.
ARG_INVALID	Input rejected with diagnostic message.

ARG_BASE

#define ARG_BASE

(

N

)

Helper for the ARG_BASE parameter in ARG_PARSER.

Note

If the conversion function doesn't take a base parameter, omit the macro like in the ARG_PARSE_F macro definition.

Parameters

N	Numeric base to pass to conversion functions, e.g. 10 for decimal or 16 for hex.

ARG_ERR

#define ARG_ERR   "Invalid value"

Default parser error message if err is empty in ARG_PARSER.

Remarks

Overridable before including args.h.

ARG_INVALID

#define ARG_INVALID

(

msg

)

Creates a failing arg_callback value.

Parameters

msg	Diagnostic message to show the user, e.g. "Must be a positive integer".