getc(3) 						     Library Functions Manual							   getc(3)

NAME

       getc, fgetc, getc_unlocked, getchar, getchar_unlocked, getw - Get a byte or word from an input stream

LIBRARY

       Standard C Library (libc)

SYNOPSIS

       #include <stdio.h>

       int getc(
	       FILE *stream);

       int fgetc(
	       FILE *stream);

       int getc_unlocked(
	       FILE * stream);

       int getchar(void);

       int getchar_unlocked(void);

       int getw(
	       FILE *stream);

STANDARDS

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

       fgetc(), getc_unlocked, getc(), getchar(), getchar_unlocked, getw(): XSH5.0

       Refer to the standards(5) reference page for more information about industry standards and associated tags.

PARAMETERS

       Points to the file structure of an open file.

DESCRIPTION

       The  getc()  function  returns the next byte from the input specified by the stream parameter and moves the file pointer, if defined, ahead
       one byte in stream. The getc() function may be a macro (depending on compile-time definitions). See the NOTES section for more information.

       The fgetc() function performs the same function as getc().

       The getchar() function returns the next byte from stdin, the standard input stream. Note that getchar() can also be a macro.

       [Tru64 UNIX]  The reentrant versions of these functions are all locked against multiple threads calling	them  simultaneously.	This  will
       incur  an  overhead  to ensure integrity of the stream. The unlocked versions of these calls, getc_unlocked() and getchar_unlocked() may be
       used to avoid the overhead. The getc_unlocked() and getchar_unlocked() functions are functionally identical to  the  getc()  and  getchar()
       functions,  except  that getc_unlocked() and getchar_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.  The  getc()
       and getchar() functions can also be macros.

       The  getw()  function reads the next word (int) from the stream.  The size of a word is the size of an int, which may vary from one machine
       architecture to another.  The getw() function returns the constant EOF at the end of the file or when an error occurs. Since EOF is a valid
       integer	value, the feof() and ferror() functions can be used to check the success of getw(). The getw() function assumes no special align-
       ment in the file.

       Because of possible differences in int length and byte ordering from one machine architecture to another, files written	using  the  putw()
       subroutine are machine dependent and may not be readable using getw() on a different type of processor.

NOTES

       The  getc() and getchar() functions may be macros (depending on the compile-time definitions used in the source).  Consequently, you cannot
       use these interfaces where a function is necessary; for example, a subroutine pointer cannot point to one of these  interfaces.	 In  addi-
       tion, getc() does not work correctly with a stream parameter that has side effects.  In particular, the following does not work:

	       getc(*f++) In cases like this one, use the fgetc() function instead.

RETURN VALUES

       Upon  successful  completion,  these  functions and macros return the next byte or word from the input stream.  If the stream is at end-of-
       file, the end-of-file indicator for the stream is set and the integer constant EOF is returned.	If a read error occurs, the error  indica-
       tor for the stream is set, EOF is returned, and errno is set to indicate the error.

ERRORS

       The  fgetc(), getc(), getc_unlocked(), getchar(), getchar_unlocked(), and getw() functions set errno to the specified value for the follow-
       ing conditions: The O_NONBLOCK flag is set for the underlying stream and the process would be delayed by  the  read  operation.	 The  file
       descriptor underlying the stream is not a valid file descriptor or is not open for reading.  The read operation was interrupted by a signal
       which was caught and no data was transferred.  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 has occurred. (This condition was defined for Issue 4 Version 2 and higher issues of the XSH specification.)
	      Insufficient memory is available for the operation.  The device associated with stream does not exist.

RELATED INFORMATION

       Functions: flockfile(3), funlockfile(3), gets(3), getwc(3), putc(3)

       Standards: standards(5) delim off

																	   getc(3)