uprintf.h File Reference

Declarations for core functions supporting printf(3c) and related capabilities. More...

#include <stdarg.h>

Go to the source code of this file.

Typedefs
typedef int(*	embtextf_putchar_fn )(int)

Functions
int	embtextf_vuprintf (embtextf_putchar_fn write_char, const char *format, va_list args)
int	embtextf_uprintf (embtextf_putchar_fn emit_char, const char *fmt,...)

Detailed Description

Declarations for core functions supporting printf(3c) and related capabilities.

This header declares configuration options and supporting material for a printf(3c) variant that emits formatted data through a per-character callback, such as putchar(3). It can be used as the basis for routines that produce formatted output on LCDs, into character buffers, or over other communications links that can provide character-oriented interface.

vuprintf formatting capabilities

The formatting capabilities of embtextf_vuprintf() are intended to be compatible with the standard C library format string interpretation, with only a few restrictions, including:

• Floating point values are not supported.
• Wide characters are not supported.

Within those limitations, all standard format flags are supported:

Flag character	Conditional on	Comments
#	EMBTEXTF_ENABLE_VUPRINTF_ALTERNATE_FORM	Emit prefix for octal and hex values
0		Zero pad output
-		Left justify
(space)		Leave blank before positive number
+		Always emit sign before converted value

Field width and (optionally) precision are supported for integer and string conversions:

Example	Conditional on	Comments
%4d		width, pad output to 4 characters
%*d		width, pad output to width passed as argument
%.3d	EMBTEXTF_ENABLE_VUPRINTF_PRECISION	precision, minimum 3 number of digits in conversion
%.*d	EMBTEXTF_ENABLE_VUPRINTF_PRECISION	precision, minimum number of digits in conversion passed as argument

Some length modifiers are supported for integer conversion:

Example	Conditional on	Comments
%d		expect input type int
%ld	EMBTEXTF_ENABLE_VUPRINTF_LONG	expect input type long
%lld	EMBTEXTF_ENABLE_VUPRINTF_LONGLONG	expect input type long long

Many conversion specifiers, excluding floating point, are supported:

Example	Conditional on	Comments
d i		Signed decimal
o	EMBTEXTF_ENABLE_VUPRINTF_OCTAL	Octal
u		Unsigned decimal
x X		Hexadecimal (lower or upper case alphabetics)
s		Null-terminated text input
c		Character value of int
p	EMBTEXTF_ENABLE_VUPRINTF_INTPTR	Pointer output

When format specifiers are not recognized by the infrastructure the unrecognized characters are emitted as output.

Homepage

http://github.com/pabigot/embtextf

Copyright

Copyright 2013, Peter A. Bigot. Licensed under BSD-3-Clause

Note

embtextf_vuprintf() contains material copyright 2006-2011, Chris Liechti.

Typedef Documentation

typedef int(* embtextf_putchar_fn)(int)

Type of function required by embtextf_vuprintf() for emitting characters. putchar(3) is the template.

Function Documentation

int embtextf_uprintf	(	embtextf_putchar_fn	emit_char,
		const char *	fmt,
			...
	)

Variadic print-via-callback function

This uses the standard va_arg facility to extract arguments and delegate the formatting to embtextf_vuprintf().

Parameters

emit_char	as with embtextf_vuprintf()
fmt	as with embtextf_vuprintf()

Returns

as with embtextf_vuprintf

int embtextf_vuprintf	(	embtextf_putchar_fn	write_char,
		const char *	format,
		va_list	args
	)

Format text collected by a variadic function.

Parameters

write_char	the function used to emit formatted characters. The interface supports using putchar for this.
format	a standard C format string
args	aggregated arguments as collected using the stdarg.h macros.

Returns

the number of characters passed to the emit_char function while generating the formatted string.

See Also

vuprintf formatting capabilities