__vprintf
OS/161 Reference Manual
Name
__vprintf - printf backend
Library
Standard C Library (libc, -lc)
Synopsis
#include <unistd.h>
int
__vprintf(void (*func)(void *clientdata,
const char *str,
size_t len),
void *clientdata, const char *format,
va_list)
Description
In OS/161, __vprintf is the back-end engine for
printf and printf-like functions.
Note that it is not portable - application code should use
snprintf or vsnprintf when implementing
their own printf-like functions. This documentation is provided for
use when extending OS/161 itself.
The format and subsequent arguments are treated as described
under printf.
The func argument is called to print text generated by the
formatting process. The clientdata argument is passed
straight through __vprintf to func. The str argument
to func points to some text that is to be printed; the len
argument is the length of that string, which should not be assumed to
be null-terminated.
The strings passed to func may be small; if printing is
expensive buffering is probably indicated.
Return Values
__vprintf returns the number of characters printed.