vprintf(3S)         (C Programming Language Utilities)          vprintf(3S)


   NAME
         vprintf, vfprintf, vsprintf - print formatted output of a variable
         argument list

   SYNOPSIS
         #include <stdio.h>
         #include <stdarg.h>
         int vprintf(const char *format, valist ap);
         int vfprintf(FILE *stream, const char *format, valist ap);
         int vsprintf(char *s, const char *format, valist ap);

   DESCRIPTION
         vprintf, vfprintf and vsprintf are the same as printf, fprintf, and
         sprintf respectively, except that instead of being called with a
         variable number of arguments, they are called with an argument list
         as defined by the <stdarg.h> header file.

         The <stdarg.h> header file defines the type valist and a set of
         macros for advancing through a list of arguments whose number and
         types may vary.  The argument ap to the vprint family of routines is
         of type valist.  This argument is used with the <stdarg.h> header
         file macros vastart, vaarg and vaend [see vastart, vaarg, and
         vaend in stdarg(5)].  The EXAMPLE section below shows their use with
         vprintf.

   EXAMPLE
         The following demonstrates how vfprintf could be used to write an
         error routine:

               #include <stdio.h>
               #include <stdarg.h>
               /*
                *   error should be called like
                *         error(functionname, format, arg1, ...);
                */
               void error(char *functionname, char *format, ...)
               {
                   valist ap;
                   vastart(ap, format);
                   /* print out name of function causing error */
                   (void) fprintf(stderr, "ERR in %s: ", functionname);
                   vaarg(ap, char*);
                   /* print out remainder of message */
                   (void) vfprintf(stderr, format, ap);
                   vaend(ap);
                   (void) abort;
               }

   SEE ALSO
         printf(3S), stdarg(5).



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   vprintf(3S)         (C Programming Language Utilities)          vprintf(3S)


   DIAGNOSTICS
         vprintf and vfprintf return the number of characters transmitted, or
         return -1 if an error was encountered.


















































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