Unix/Linux Go Back    


SuSE 11.3 - man page for ungetc (suse section 3)

Linux & Unix Commands - Search Man Pages
Man Page or Keyword Search:   man
Select Man Page Set:       apropos Keyword Search (sections above)


GETS(3) 			    Linux Programmer's Manual				  GETS(3)

NAME
       fgetc, fgets, getc, getchar, gets, ungetc - input of characters and strings

SYNOPSIS
       #include <stdio.h>

       int fgetc(FILE *stream);

       char *fgets(char *s, int size, FILE *stream);

       int getc(FILE *stream);

       int getchar(void);

       char *gets(char *s);

       int ungetc(int c, FILE *stream);

DESCRIPTION
       fgetc() reads the next character from stream and returns it as an unsigned char cast to an
       int, or EOF on end of file or error.

       getc() is equivalent to fgetc() except that it may be implemented as a macro which  evalu-
       ates stream more than once.

       getchar() is equivalent to getc(stdin).

       gets()  reads a line from stdin into the buffer pointed to by s until either a terminating
       newline or EOF, which it replaces with '\0'.  No check for  buffer  overrun  is	performed
       (see BUGS below).

       fgets()	reads  in  at most one less than size characters from stream and stores them into
       the buffer pointed to by s.  Reading stops after an EOF or a newline.   If  a  newline  is
       read, it is stored into the buffer.  A '\0' is stored after the last character in the buf-
       fer.

       ungetc() pushes c back to stream, cast to unsigned char, where it is available for  subse-
       quent read operations.  Pushed-back characters will be returned in reverse order; only one
       pushback is guaranteed.

       Calls to the functions described here can be mixed with each other and with calls to other
       input functions from the stdio library for the same input stream.

       For nonlocking counterparts, see unlocked_stdio(3).

RETURN VALUE
       fgetc(), getc() and getchar() return the character read as an unsigned char cast to an int
       or EOF on end of file or error.

       gets() and fgets() return s on success, and NULL on error or when end of file occurs while
       no characters have been read.

       ungetc() returns c on success, or EOF on error.

CONFORMING TO
       C89, C99, POSIX.1-2001.	LSB deprecates gets().	POSIX.1-2008 removes the specification of
       gets().

BUGS
       Never use gets().  Because it is impossible to tell without knowing the	data  in  advance
       how many characters gets() will read, and because gets() will continue to store characters
       past the end of the buffer, it is extremely dangerous to use.  It has been used	to  break
       computer security.  Use fgets() instead.

       It  is not advisable to mix calls to input functions from the stdio library with low-level
       calls to read(2) for the file descriptor associated with the  input  stream;  the  results
       will be undefined and very probably not what you want.

SEE ALSO
       read(2),  write(2),  ferror(3),	fgetwc(3),  fgetws(3), fopen(3), fread(3), fseek(3), get-
       line(3), getwchar(3), puts(3), scanf(3), ungetwc(3), unlocked_stdio(3)

COLOPHON
       This page is part of release 3.25 of the Linux man-pages project.  A  description  of  the
       project,   and	information  about  reporting  bugs,  can  be  found  at  http://www.ker-
       nel.org/doc/man-pages/.

GNU					    2008-08-06					  GETS(3)
Unix & Linux Commands & Man Pages : ©2000 - 2018 Unix and Linux Forums


All times are GMT -4. The time now is 12:43 PM.