getwc(3) Library Functions Manual getwc(3)
NAME
getwc, getwc_unlocked, fgetwc, getwchar - Get a wide character from an input stream
LIBRARY
Standard C Library (libc)
SYNOPSIS
#include <stdio.h> #include <wchar.h>
wint_t getwc( FILE *stream);
wint_t getwc_unlocked( FILE *stream);
wint_t fgetwc( FILE *stream);
#include <wchar.h>
wint_t getwchar(void);
STANDARDS
Interfaces documented on this reference page conform to industry standards as follows:
fgetwc(), getwc(), getwchar(): XSH5.0
Refer to the standards(5) reference page for more information about industry standards and associated tags.
PARAMETERS
Specifies an input stream from a file.
DESCRIPTION
The fgetwc() function gets the next character from the input stream specified by the stream parameter, converts it to a wide-character
code, and advances the associated file position indicator for the stream. If an error occurs, the file position indicator is indetermi-
nate. This function also marks the st_atime field of the file associated with stream for update.
The getwc() function performs the same function as fgetwc() but can be implemented as a macro on implementations that conform to X/Open
standards.
The getwchar() function gets the next wide character from the standard input stream. This function is equivalent to getwc(stdin).
The getwc_unlocked() function is functionally identical to the getwc() function, except that getwc_unlocked() may be safely used only
within a scope that is protected by the flockfile() and funlockfile() functions used as a pair. The caller must ensure that the stream is
locked before these functions are used.
On return from calls to the preceding functions, applications should use ferror() and feof() to distinguish between error and end-of-file
conditions.
NOTES
Because getwc() can be implemented as a macro, applications should not use it with a stream argument that is an expression with side
effects (for example, getwc(*f++)). The fgetwc() function is recommended over getwc() for reading characters from a stream associated with
a file.
If the value returned by the getwchar() function is stored into a variable of type wchar_t and then compared to the macro WEOF (defined as
type wint_t in the wchar.h header file), the comparison may never succeed.
RETURN VALUES
These functions return either the resultant wide-character code or, for error and end-of-file conditions, the constant WEOF (wide-character
End-Of-File).
ERRORS
If any of the following conditions occur, the fgetwc(), getwc(), getwc_unlocked(), and getwchar(), functions set errno to the corresponding
value: The O_NONBLOCK flag is set for the file descriptor underlying the stream parameter and the process would be delayed by the read
operation. The file descriptor underlying the stream parameter is not a valid file descriptor open for reading. The data obtained from
the input stream does not form a valid wide character in the current locale. The read operation was interrupted by a signal that was
caught, and no data was transferred. One of the following errors occurred: The call is attempting to read from the process's controlling
terminal and either the process is ignoring or blocking the SIGTTIN signal or the process group is orphaned. A physical I/O error
occurred. This condition is defined starting with XSH Issue 4, Version 2. Insufficient memory is available for the operation. The device
associated with stream either does not exist or cannot handle the request. The file is a regular file and an attempt was made to read at
or beyond the offset maximum associated with the corresponding stream.
RELATED INFORMATION
Functions: fopen(3), fread(3), fgetws(3), getc(3), gets(3), putwc(3), scanf(3), wscanf(3)
Standards: standards(5) delim off
getwc(3)