The vfprintf() function is used to convert formatted string to specific output. It returns the length of the outputted string.
Syntax
vfprintf(stream, format, arg)
Parameters
stream − Specifies where to output the string
format − Specifies the string and how to format the variables in it.
The following are the possible format values −
%% − Returns a percent sign
%b − Binary number
%c − The character according to the ASCII value
%d − Signed decimal number (negative, zero or positive)
%e − Scientific notation using a lowercase (e.g. 1.2e+2)
%E − Scientific notation using a uppercase (e.g. 1.2E+2)
%u − Unsigned decimal number (equal to or greater than zero)
%f − Floating-point number (local settings aware)
%F − Floating-point number (not local settings aware)
%g − shorter of %e and %f
%G − shorter of %E and %f
%o − Octal number
%s − String
%x − Hexadecimal number (lowercase letters)
%X − Hexadecimal number (uppercase letters)
arg − An array with arguments to be inserted at the % signs in the format string.
Return
The vfprintf() function returns the length of the outputted string.
Example
The following is an example −
<?php
$str1 = 123;
$str2 = 456;
$file = fopen("sample.txt","r");
vfprintf($file,"%f%f",array($str1,$str2));
?>