printf

Writes formatted output to a specified file designated by stdout.

Library:LibC
Classification:ANSI
Service:File and Directory I/O

Syntax

  #include <stdio.h> 
   
  int printf (
     const char   *format,   
     ... );

Parameters

format

(IN) Points to the format control string. See Print Format Control Strings.

...

(IN) Points to an argument for a conversion specifier. The number of arguments is determined by the format string.

Return Values

If successful, returns the number of characters written. Otherwise, returns a negative value and sets errno to one of the following:

Decimal

Constant

Description

4

EBADF

The file descriptor is not a valid file descriptor open for writing.

5

ENOMEM

Insufficient storage space is available.

12

ENOSPC

No free space remains on the device containing the file.

24

EAGAIN

The O_NONBLOCK flag is set for the file descriptor, and the process cannot immediately perform the write operation.

25

ENXIO

A request was made of a nonexistent device, or the request was outside the capabilities of the device.

28

EIO

A physical I/O error has occurred.

32

EPIPE

An attempt was made to write to a pipe or FIFO that is not open for reading by any process.

63

EINTR

A signal interrupted the write operation.

71

EFBIG

An attempt was made to write to a file that exceeds the maximum file size.

Remarks

The printf function writes output to the file designated by stdout under control of the format parameter.

For example, a specifier of the form %8.*f defines a field to be at least 8 characters wide and gets the next argument for the precision to be used in the conversion.

The output from

  printf ("f1 = %8.4f f2 = %10.2E x = %#08x i = %d",  
        23.45,   3141.5926,   0x1db,     -1 );

would be

  f1 =  23.4500 f2 =   3.14E+003 x = 0x0001db i = -1

You can also use strings similar to the following:

  printf ("Test: %3$s %2$d %1$s", string, 10, string);

See Also