Format
#include <wchar.h>
#include <stdio.h>
wint_t fgetwc(FILE *stream);Language Level: ANSI
Threadsafe: Yes.
Locale Sensitive: The behavior of this function might be affected by the LC_CTYPE category of the current locale. The behavior might also be affected by the LC_UNI_CTYPE category of the current locale if LOCALETYPE(*LOCALEUCS2) or LOCALETYPE(*LOCALEUTF) is specified on the compilation command. This function is not available when LOCALETYPE(*CLD) is specified on the compilation command. For more information, see Understanding CCSIDs and Locales.
Integrated File System Interface: This function is not available when SYSIFCOPT(*NOIFSIO) is specified on the compilation command.
Wide Character Function: See Wide Characters for more information.
Description
The fgetwc() reads the next multibyte character from the input stream pointed to by stream, converts it to a wide character, and advances the associated file position indicator for the stream (if defined).
Using non-wide-character functions with fgetwc() on the same stream results in undefined behavior. After calling fgetwc(), flush the buffer or reposition the stream pointer before calling a write function for the stream, unless EOF has been reached. After a write operation on the stream, flush the buffer or reposition the stream pointer before calling fgetwc().
Return Value
The fgetwc() function returns the next wide character that corresponds to the multibyte character from the input stream pointed to by stream. If the stream is at EOF, the EOF indicator for the stream is set, and fgetwc() returns WEOF.
If a read error occurs, the error indicator for the stream is set, and the fgetwc() function returns WEOF. If an encoding error occurs (an error converting the multibyte character into a wide character), the fgetwc() function sets errno to EILSEQ and returns WEOF.
Use the ferror() and feof() functions to distinguish between a read error and an EOF. EOF is only reached when an attempt is made to read past the last byte of data. Reading up to and including the last byte of data does not turn on the EOF indicator.
The value of errno can be set to:
Example that uses fgetwc()
This example opens a file, reads in each wide character, and prints out the characters.
#include <stdio.h>
#include <stdlib.h>
#include <wchar.h>
#include <errno.h>
int main(void)
{
FILE *stream;
wint_t wc;
if (NULL == (stream = fopen("fgetwc.dat", "r"))) {
printf("Unable to open: \"fgetwc.dat\"\n");
exit(1);
}
errno = 0;
while (WEOF != (wc = fgetwc(stream)))
printf("wc = %lc\n", wc);
if (EILSEQ == errno) {
printf("An invalid wide character was encountered.\n");
exit(1);
}
fclose(stream);
return 0;
}
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