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vprintf(3)
NAME
  vprintf, vfprintf, vsnprintf, vsprintf - Format a variable number of
  parameters for output

SYNOPSIS
  #include <stdarg.h>
  #include <stdio.h>

  int vprintf(
	  const char *format,
	  va_list printarg );

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

  int vsnprintf(
	  char *string,
	  size_t n,
	  const char *format,
	  va_list printarg );

  int vsprintf(
	  char *string,
	  const char *format,
	  va_list printarg );

LIBRARY
  Standard C Library (libc)

STANDARDS
  Interfaces documented on this reference page conform to industry standards
  as follows:

  vfprintf(), vprintf(), vsnprintf(), vsprintf():  ISO C, XPG4, XPG4-UNIX

  Refer to the standards(5) reference page for more information about
  industry standards and associated tags.

PARAMETERS
  format
      Specifies a character string that contains two types of objects:

	·  Plain characters, which are copied to the output stream.

	·  Conversion specifications, each of which causes zero or more items
	   to be fetched from the stdarg parameter lists.

  printarg
      Specifies the arguments to be printed.

  stream
      Specifies the output stream.

  string
      Specifies the buffer to which output is printed.

  n   Specifies the size of the buffer referred to by string.

DESCRIPTION
  The vprintf(), vfprintf(), vsnprintf(), and vsprintf() functions format and
  write stdarg parameter lists.

  These functions are the same as the printf(), fprintf(), snprintf(), and
  sprintf() functions, respectively, except that these functions are not
  called with a variable number of parameters. Instead, vprintf(),
  vfprintf(), vsnprintf(), and vsprintf() are called with a parameter list
  pointer as defined by stdarg. Because these functions invoke the va_arg()
  macro and not the va_end() macro, the value of printarg is indeterminate
  after a return. Therefore, applications should execute a call to the
  va_end() macro after a call to one of these functions.

EXAMPLES
  The following example demonstrates how the vfprintf() function can be used
  to write an error routine:

       #include <stdarg.h>
       #include <stdio.h>

       void    error(char *funct, char *fmt, ...)
       {
	       va_list args;
	       /*
	       ** Display the name of the function that called error
	       */
	       fprintf(stderr, "ERROR in %s: ", funct);
	       /*
	       ** Display the remainder of the message
	       */
	       va_start(args, fmt);
	       vfprintf(stderr, fmt, args);
	       va_end(args);
	       abort();
       }

SEE ALSO
  Functions: fopen(3), printf(3), vwprintf(3), wprintf(3)

Index for Section 3

Alphabetical listing for V

Top of page