Format
#include <stdio.h>
#include <wchar.h>
wint_t getwc(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. It 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 getwc() function reads the next multibyte character from stream, converts it to a wide character, and advances the associated file position indicator for stream.
The getwc() function is equivalent to the fgetwc() function except that, if it is implemented as a macro, it can evaluate stream more than once. Therefore, the argument should never be an expression with side effects.
If the current locale is changed between subsequent read operations on the same stream, undefined results can occur. Using non-wide-character functions with the getwc() function on the same stream results in undefined behavior.
After calling the getwc() function, 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 the getwc() function.
Return Value
The getwc() function returns the next wide character from the input stream, or WEOF. If an error occurs, the getwc() function sets the error indicator. If the getwc() function encounters the end-of-file, it sets the EOF indicator. If an encoding error occurs during conversion of the multibyte character, the getwc() function sets errno to EILSEQ.
Use the ferror() or feof() functions to determine whether an error or an EOF condition occurred. 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.
For information about errno values for getwc(), see fgetwc() — Read Wide Character from Stream.
Example that uses getwc()
#include <stdio.h>
#include <stdlib.h>
#include <wchar.h>
#include <errno.h>
int main(void)
{
FILE *stream;
wint_t wc;
if (NULL == (stream = fopen("getwc.dat", "r"))) {
printf("Unable to open: \"getwc.dat\"\n");
exit(1);
}
errno = 0;
while (WEOF != (wc = getwc(stream)))
printf("wc = %lc\n", wc);
if (EILSEQ == errno) {
printf("An invalid wide character was encountered.\n");
exit(1);
}
fclose(stream);
return 0;
/********************************************************
Assuming the file getwc.dat contains:
Hello world!
The output should be similar to:
wc = H
wc = e
wc = l
wc = l
wc = o
:
********************************************************/
}Related Information