vsscanf, vswscanf

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Header File

stdio.h

Category

Formatted input/output functions

Prototype

int vsscanf(const char *buffer, const char *format, va_list arglist);

int vswscanf(const wchar_t *buffer, const wchar_t *format, va_list arglist);

Description

Scans and formats input from a stream.

The v...scanf functions are known as alternate entry points for the ...scanf functions. They behave exactly like their ...scanf counterparts, but they accept a pointer to a list of arguments instead of an argument list.

Remarque :  For details on format specifiers, see scanf Format Specifiers.

vsscanf scans a series of input fields, one character at a time, reading from a stream. Then each field is formatted according to a format specifier passed to vsscanf in the format string pointed to by format. Finally, vsscanf stores the formatted input at an address passed to it as an argument following format. There must be the same number of format specifiers and addresses as there are input fields.

vsscanf might stop scanning a particular field before it reaches the normal end-of-field (whitespace) character, or it might terminate entirely, for a number of reasons. See scanf for a discussion of possible causes.

Return Value

vsscanf returns the number of input fields successfully scanned, converted, and stored; the return value does not include scanned fields that were not stored. If no fields were stored, the return value is 0.

If vsscanf attempts to read at end-of-string, the return value is EOF.

Example

  1. include <stdio.h>
#include <stdarg.h>
char buffer[80] = "30 90.0 abc";
int vssf(char *fmt, ...)
{
   va_list  argptr;
   int cnt;
   fflush(stdin);
   va_start(argptr, fmt);
   cnt = vsscanf(buffer, fmt, argptr);
   va_end(argptr);
   return(cnt);
}
int main(void)
{
   int inumber;
   float fnumber;
   char string[80];
   vssf("%d %f %s", &inumber, &fnumber, string);
   printf("%d %f %s\n", inumber, fnumber, string);
   return 0;
}

Portability

POSIX Win32 ANSI C ANSI C++

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See Also