Content-type: text/html Man page of getwc

getwc

Section: C Library Functions (3)
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NAME

getwc, getwc_unlocked, fgetwc, getwchar - Get a wide character from an input stream  

LIBRARY

Standard C Library (libc.so, libc.a)  

SYNOPSIS

#include <wchar.h>

wint_t getwc(        FILE *stream);

wint_t getwc_unlocked(        FILE *stream);

wint_t fgetwc(        FILE *stream);

wint_t getwchar(void);

For the fgetwc() and getwc() functions, application developers may want to specify an #include statement for <stdio.h> before the one for <wchar.h> if programs are being developed for multiple platforms. The additional #include statement is not required on Tru64 UNIX systems or by ISO or X/Open standards, but may be required on other vendors' systems that conform to these standards.  

STANDARDS

Interfaces documented on this reference page conform to industry standards as follows:

fgetwc(), getwc(), getwchar(): XPG4, XPG4-UNIX

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 indeterminate. 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. [XPG4-UNIX]  A physical I/O error occurred. Insufficient memory is available for the operation. The device associated with stream either does not exist or cannot handle the request.  

RELATED INFORMATION

Functions: fopen(3), fread(3), fgetws(3), getc(3), gets(3), putwc(3), scanf(3), wscanf(3)

Standards: standards(5) delim off


 

Index

NAME
LIBRARY
SYNOPSIS
STANDARDS
PARAMETERS
DESCRIPTION
NOTES
RETURN VALUES
ERRORS
RELATED INFORMATION

This document was created by man2html, using the manual pages.
Time: 02:42:28 GMT, October 02, 2010