The Open Group Base Specifications Issue 7, 2018 edition
IEEE Std 1003.1-2017 (Revision of IEEE Std 1003.1-2008)
Copyright © 2001-2018 IEEE and The Open Group

NAME

vdprintf, vfprintf, vprintf, vsnprintf, vsprintf - format output of a stdarg argument list

SYNOPSIS

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

[CX] [Option Start] int vdprintf(int fildes, const char *restrict format, va_list ap); [Option End]

int vfprintf(FILE *restrict
stream, const char *restrict format,
       va_list
ap);
int vprintf(const char *restrict
format, va_list ap);
int vsnprintf(char *restrict
s, size_t n, const char *restrict format,
       va_list
ap);
int vsprintf(char *restrict
s, const char *restrict format, va_list ap);

DESCRIPTION

[CX] [Option Start] The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional. This volume of POSIX.1-2017 defers to the ISO C standard. [Option End]

The [CX] [Option Start] vdprintf(), [Option End] vfprintf(), vprintf(), vsnprintf(), and vsprintf() functions shall be equivalent to the [CX] [Option Start] dprintf(), [Option End] fprintf(), printf(), snprintf(), and sprintf() functions respectively, except that instead of being called with a variable number of arguments, they are called with an argument list as defined by <stdarg.h>.

These functions shall not invoke the va_end macro. As these functions invoke the va_arg macro, the value of ap after the return is unspecified.

RETURN VALUE

Refer to fprintf.

ERRORS

Refer to fprintf.


The following sections are informative.

EXAMPLES

None.

APPLICATION USAGE

Applications using these functions should call va_end(ap) afterwards to clean up.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

Standard I/O Streams, fprintf

XBD <stdarg.h>, <stdio.h>

CHANGE HISTORY

First released in Issue 1. Derived from Issue 1 of the SVID.

Issue 5

The vsnprintf() function is added.

Issue 6

The vfprintf(), vprintf(), vsnprintf(), and vsprintf() functions are updated for alignment with the ISO/IEC 9899:1999 standard.

Issue 7

The vdprintf() function is added to complement the dprintf() function from The Open Group Technical Standard, 2006, Extended API Set Part 1.

POSIX.1-2008, Technical Corrigendum 1, XSH/TC1-2008/0703 [14] is applied.

End of informative text.

 

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