C Language: vfprintf function(Formatted File Write Using Variable Argument List)

In the C Programming Language, the vfprintf function writes formatted output to stream using arg as the variable argument list.


The syntax for the vfprintf function in the C Language is:

int vfprintf(FILE *stream, const char *format, va_list arg);

Parameters or Arguments


The stream where the output will be written.


Describes the output as well as provides a placeholder to insert the formatted string. Here are a few examples:

Format Explanation Example
%d Display an integer 10
%f Displays a floating-point number in fixed decimal format 10.500000
%.1f Displays a floating-point number with 1 digit after the decimal 10.5
%e Display a floating-point number in exponential (scientific notation) 1.050000e+01
%g Display a floating-point number in either fixed decimal or exponential format depending on the size of the number (will not display trailing zeros) 10.5


A variable argument list.


The vfprintf function returns the number of characters that was written. If an error occurs, it will return a negative value.

Required Header

In the C Language, the required header for the vfprintf function is:

#include <stdio.h>

Applies To

In the C Language, the vfprintf function can be used in the following versions:

  • ANSI/ISO 9899-1990

stdio.h Functions