1VFPRINTF(3P)               POSIX Programmer's Manual              VFPRINTF(3P)
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PROLOG

6       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
7       implementation of this interface may differ (consult the  corresponding
8       Linux  manual page for details of Linux behavior), or the interface may
9       not be implemented on Linux.
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NAME

12       vdprintf, vfprintf, vprintf, vsnprintf, vsprintf — format output  of  a
13       stdarg argument list
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SYNOPSIS

16       #include <stdarg.h>
17       #include <stdio.h>
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19       int vdprintf(int fildes, const char *restrict format, va_list ap);
20       int vfprintf(FILE *restrict stream, const char *restrict format,
21           va_list ap);
22       int vprintf(const char *restrict format, va_list ap);
23       int vsnprintf(char *restrict s, size_t n, const char *restrict format,
24           va_list ap);
25       int vsprintf(char *restrict s, const char *restrict format, va_list ap);
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DESCRIPTION

28       The  functionality described on this reference page is aligned with the
29       ISO C standard. Any conflict between the  requirements  described  here
30       and  the  ISO C  standard is unintentional. This volume of POSIX.1‐2017
31       defers to the ISO C standard.
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33       The vdprintf(),  vfprintf(),  vprintf(),  vsnprintf(),  and  vsprintf()
34       functions  shall  be equivalent to the  dprintf(), fprintf(), printf(),
35       snprintf(), and sprintf() functions respectively, except  that  instead
36       of  being  called  with a variable number of arguments, they are called
37       with an argument list as defined by <stdarg.h>.
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39       These functions shall not invoke the va_end macro. As  these  functions
40       invoke  the  va_arg macro, the value of ap after the return is unspeci‐
41       fied.
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RETURN VALUE

44       Refer to fprintf().
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ERRORS

47       Refer to fprintf().
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49       The following sections are informative.
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EXAMPLES

52       None.
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APPLICATION USAGE

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

59       None.
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FUTURE DIRECTIONS

62       None.
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SEE ALSO

65       Section 2.5, Standard I/O Streams, fprintf()
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67       The Base Definitions volume of POSIX.1‐2017, <stdarg.h>, <stdio.h>
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70       Portions  of  this text are reprinted and reproduced in electronic form
71       from IEEE Std 1003.1-2017, Standard for Information Technology --  Por‐
72       table  Operating System Interface (POSIX), The Open Group Base Specifi‐
73       cations Issue 7, 2018 Edition, Copyright (C) 2018 by the  Institute  of
74       Electrical  and  Electronics Engineers, Inc and The Open Group.  In the
75       event of any discrepancy between this version and the original IEEE and
76       The  Open Group Standard, the original IEEE and The Open Group Standard
77       is the referee document. The original Standard can be  obtained  online
78       at http://www.opengroup.org/unix/online.html .
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80       Any  typographical  or  formatting  errors that appear in this page are
81       most likely to have been introduced during the conversion of the source
82       files  to  man page format. To report such errors, see https://www.ker‐
83       nel.org/doc/man-pages/reporting_bugs.html .
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87IEEE/The Open Group                  2017                         VFPRINTF(3P)
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