PHP: Hypertext Preprocessor (original) (raw)

vfprintf

(PHP 5, PHP 7, PHP 8)

vfprintf — Write a formatted string to a stream

Description

Operates as fprintf() but accepts an array of arguments, rather than a variable number of arguments.

Parameters

stream

format

The format string is composed of zero or more directives: ordinary characters (excluding %) that are copied directly to the result and conversion specifications, each of which results in fetching its own parameter.

A conversion specification follows this prototype:%[argnum$][flags][width][.precision]specifier.

Argnum

An integer followed by a dollar sign $, to specify which number argument to treat in the conversion.

Flags

Flag	Description
-	Left-justify within the given field width; Right justification is the default
+	Prefix positive numbers with a plus sign+; Default only negative are prefixed with a negative sign.
(space)	Pads the result with spaces. This is the default.
0	Only left-pads numbers with zeros. With s specifiers this can also right-pad with zeros.
'(char)	Pads the result with the character (char).

Width

Either an integer that says how many characters (minimum) this conversion should result in, or *. If * is used, then the width is supplied as an additional integer value preceding the one formatted by the specifier.

Precision

A period . optionally followed by either an integer or *, whose meaning depends on the specifier:

For e, E,f and F specifiers: this is the number of digits to be printed after the decimal point (by default, this is 6).
For g, G,h and H specifiers: this is the maximum number of significant digits to be printed.
For s specifier: it acts as a cutoff point, setting a maximum character limit to the string.

Note: If the period is specified without an explicit value for precision, 0 is assumed. If * is used, the precision is supplied as an additional integer value preceding the one formatted by the specifier.

Specifiers

Specifier	Description
%	A literal percent character. No argument is required.
b	The argument is treated as an integer and presented as a binary number.
c	The argument is treated as an integer and presented as the character with that ASCII.
d	The argument is treated as an integer and presented as a (signed) decimal number.
e	The argument is treated as scientific notation (e.g. 1.2e+2).
E	Like the e specifier but uses uppercase letter (e.g. 1.2E+2).
f	The argument is treated as a float and presented as a floating-point number (locale aware).
F	The argument is treated as a float and presented as a floating-point number (non-locale aware).
g	General format. Let P equal the precision if nonzero, 6 if the precision is omitted, or 1 if the precision is zero. Then, if a conversion with style E would have an exponent of X: If P > X ≥ −4, the conversion is with style f and precision P − (X + 1). Otherwise, the conversion is with style e and precision P − 1.
G	Like the g specifier but usesE and f.
h	Like the g specifier but uses F. Available as of PHP 8.0.0.
H	Like the g specifier but usesE and F. Available as of PHP 8.0.0.
o	The argument is treated as an integer and presented as an octal number.
s	The argument is treated and presented as a string.
u	The argument is treated as an integer and presented as an unsigned decimal number.
x	The argument is treated as an integer and presented as a hexadecimal number (with lowercase letters).
X	The argument is treated as an integer and presented as a hexadecimal number (with uppercase letters).

Warning

The c type specifier ignores padding and width.

Warning

Attempting to use a combination of the string and width specifiers with character sets that require more than one byte per character may result in unexpected results.

Variables will be co-erced to a suitable type for the specifier:

Type Handling

Type	Specifiers
string	s
int	d,u,c,o,x,X,b
float	e,E,f,F,g,G,h,H

values

Return Values

Returns the length of the outputted string.

Errors/Exceptions

As of PHP 8.0.0, a ValueError is thrown if the number of arguments is zero. Prior to PHP 8.0.0, a [E_WARNING](errorfunc.constants.php#constant.e-warning) was emitted instead.

As of PHP 8.0.0, a ValueError is thrown if [width] is less than zero or bigger than [PHP_INT_MAX](reserved.constants.php#constant.php-int-max). Prior to PHP 8.0.0, a [E_WARNING](errorfunc.constants.php#constant.e-warning) was emitted instead.

As of PHP 8.0.0, a ValueError is thrown if [precision] is less than zero or bigger than [PHP_INT_MAX](reserved.constants.php#constant.php-int-max). Prior to PHP 8.0.0, a [E_WARNING](errorfunc.constants.php#constant.e-warning) was emitted instead.

As of PHP 8.0.0, a ValueError is thrown when less arguments are given than required. Prior to PHP 8.0.0, [false](reserved.constants.php#constant.false) was returned and a [E_WARNING](errorfunc.constants.php#constant.e-warning) emitted instead.

Changelog

Version	Description
8.0.0	This function no longer returns false on failure.
8.0.0	Throw a ValueError if the number of arguments is zero; previously this function emitted a E_WARNING instead.
8.0.0	Throw a ValueError if [width] is less than zero or bigger than PHP_INT_MAX; previously this function emitted a E_WARNING instead.
8.0.0	Throw a ValueError if [precision] is less than zero or bigger than PHP_INT_MAX; previously this function emitted a E_WARNING instead.
8.0.0	Throw a ValueError when less arguments are given than required; previously this function emitted a E_WARNING instead.

Examples

Example #1 vfprintf(): zero-padded integers

<?php if (!($fp = fopen('date.txt', 'w'))) return;$year = 2025; $month = 5; $day = 6; vfprintf($fp, "%04d-%02d-%02d", array($year, <math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>m</mi><mi>o</mi><mi>n</mi><mi>t</mi><mi>h</mi><mo separator="true">,</mo></mrow><annotation encoding="application/x-tex">month, </annotation></semantics></math>month,day)); // will write the formatted ISO date to date.txt ?>

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