Writes output to the stream under control of the wide-character
format string.
Format
#include <wchar.h>
int fwprintf (FILE *stream, const wchar_t *format, . . . );
1 – Arguments
stream
A file pointer.
format
A pointer to a wide-character string containing the format
specifications.
. . .
Optional expressions whose resultant types correspond to
conversion specifications given in the format specification.
If no conversion specifications are given, the output sources can
be omitted. Otherwise, the function calls must have exactly as
many output sources as there are conversion specifications, and
the conversion specifications must match the types of the output
sources.
Conversion specifications are matched to output sources in left-
to-right order. Any excess output sources are ignored.
2 – Description
The fwprintf function writes output to the stream pointed to by
stream under control of the wide-character string pointed to by
format, which specifies how to convert subsequent arguments to
output. If there are insufficient arguments for the format, the
behavior is undefined. If the format is exhausted while arguments
remain, the excess arguments are evaluated, but are otherwise
ignored. The fwprintf function returns when it encounters the end
of the format string.
The format argument is composed of zero or more directives that
include:
o Ordinary wide characters (not the percent sign (%))
o Conversion specifications
3 – Return Values
n The number of wide characters written.
Negative value Indicates an error. The function sets errno to
one of the following:
o EILSEQ - Invalid character detected.
o EINVAL - Insufficient arguments.
o ENOMEM - Not enough memory available for
conversion.
o ERANGE - Floating-point calculations
overflow.
o EVMSERR - Nontranslatable OpenVMS error.
vaxc$errno contains the OpenVMS error code.
This might indicate that conversion to a
numeric value failed because of overflow.
The function can also set errno to the
following as a result of errors returned from
the I/O subsystem:
o EBADF - The file descriptor is not valid.
o EIO - I/O error.
o ENOSPC - No free space on the device
containing the file.
o ENXIO - Device does not exist.
o EPIPE - Broken pipe.
o ESPIPE - Illegal seek in a file opened for
append.
o EVMSERR - Nontranslatable OpenVMS error.
vaxc$errno contains the OpenVMS error code.
This indicates that an I/O error occurred
for which there is no equivalent C error
code.
4 – Example
The following example shows how to print a date and time in the
form "Sunday, July 3, 10:02", followed by pi to five decimal
places:
#include <math.h>
#include <stdio.h>
#include <wchar.h>
/* . . . */
wchar_t *weekday, *month; /* pointers to wide-character strings */
int day, hours, min;
fwprintf(stdout, L"%ls, %ls %d, %.2d:%.2d\n",
weekday, month, day, hour, min);
fwprintf(stdout, L"pi = %.5f\n", 4 * atan(1.0));