c/io/vfprintf

Loads the data from the locations, defined by, converts them to character string equivalents and writes the results to a variety of sinks.

@1@ Writes the results to stdout. @2@ Writes the results to a file stream. @3@ Writes the results to a character string. @4@ Writes the results to a character string. At most characters are written. The resulting character string will be terminated with a null character, unless is zero. If is zero, nothing is written and  may be a null pointer, however the return value (number of bytes that would be written not including the null terminator) is still calculated and returned. @5-8@ Same as, except that the following errors are detected at runtime and call the currently installed constraint handler function:
 * the conversion specifier is present in
 * any of the arguments corresponding to is a null pointer
 * or is a null pointer
 * is zero or greater than rsize_max
 * encoding errors occur in any of string and character conversion specifiers
 * (for only), the string to be stored in  (including the trailing null)) would be exceed

Return value
@1-3@ The number of characters written if successful or negative value if an error occurred. @4@ The number of characters written if successful or negative value if an error occurred. If the resulting string gets truncated due to limit, function returns the total number of characters (not including the terminating null-byte) which would have been written, if the limit was not imposed. @5,6@ number of characters transmitted to the output stream or negative value if an output error, a runtime constrants violation error, or an encoding error occurred. @7@ number of characters written to, not counting the null character (which is always written as long as is not a null pointer and  is not zero and not greater than ), or zero on runtime constraint violations, and negative value on encoding errors @8@ number of characters not including the terminating null character (which is always written as long as is not a null pointer and  is not zero and not greater than ), which would have been written to  if  was ignored, or a negative value if a runtime constraints violation or an encoding error occurred