vprintf
, vfprintf
, vsprintf
—format argument list#include <stdio.h> #include <stdarg.h> int vprintf(const char *fmt, va_list list); int vfprintf(FILE *fp, const char *fmt, va_list list); int vsprintf(char *str, const char *fmt, va_list list); int vasprintf(char **strp, const char *fmt, va_list list); int vsnprintf(char *str, size_t size, const char *fmt, va_list list); int _vprintf_r(struct _reent *reent, const char *fmt, va_list list); int _vfprintf_r(struct _reent *reent, FILE *fp, const char *fmt, va_list list); int _vasprintf_r(struct _reent *reent, char **str, const char *fmt, va_list list); int _vsprintf_r(struct _reent *reent, char *str, const char *fmt, va_list list); int _vsnprintf_r(struct _reent *reent, char *str, size_t size, const char *fmt, va_list list);
Description
vprintf
, vfprintf
, vasprintf
, vsprintf
and vsnprintf
are
(respectively) variants of printf
, fprintf
, asprintf
, sprintf
,
and snprintf
. They differ only in allowing their caller to pass the
variable argument list as a va_list
object (initialized by va_start
)
rather than directly accepting a variable number of arguments.
Returns
The return values are consistent with the corresponding functions:
vasprintf
/vsprintf
returns the number of bytes in the output string,
save that the concluding NULL
is not counted.
vprintf
and vfprintf
return the number of characters transmitted.
If an error occurs, vprintf
and vfprintf
return EOF
and
vasprintf
returns -1. No error returns occur for vsprintf
.
Portability
ANSI C requires all three functions.
Supporting OS subroutines required: close
, fstat
, isatty
,
lseek
, read
, sbrk
, write
.