(PHP 5, PHP 7, PHP 8)
vfprintf — Write a formatted string to a stream
Write a string produced according to format to the
stream resource specified by stream.
Operates as fprintf() but accepts an array of arguments, rather than a variable number of arguments.
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.
An integer followed by a dollar sign $,
to specify which number argument to treat in the conversion.
| 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). |
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.
A period . optionally followed by
either an integer or *,
whose meaning depends on the specifier:
e, E,
f and F
specifiers: this is the number of digits to be printed
after the decimal point (by default, this is 6).
g, G,
h and H
specifiers: this is the maximum number of significant
digits to be printed.
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.
| 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 uses
E and f.
|
h |
Like the g specifier but uses F.
Available as of PHP 8.0.0.
|
H |
Like the g specifier but uses
E 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). |
The c type specifier ignores padding and width.
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 | Specifiers |
|---|---|
| string | s |
| int |
d,
u,
c,
o,
x,
X,
b
|
| float |
e,
E,
f,
F,
g,
G,
h,
H
|
values
Returns the length of the outputted string.
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 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.
Prior to PHP 8.0.0, a 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.
Prior to PHP 8.0.0, a 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 was returned and a E_WARNING emitted instead.
| 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.
|
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, $month, $day));
// will write the formatted ISO date to date.txt
?>