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 a null byte ('\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 terminating null byte ('\0') is stored after the
       last character in the buffer.

       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 marks gets() obsolescent.  ISO C11 removes the speci-
       fication of gets() from the C language, and since version 2.16, glibc header  files  don't
       expose the function declaration if the _ISOC11_SOURCE feature test macro is defined.

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),   fea-
       ture_test_macros(7)

COLOPHON
       This page is part of release 3.53 of the Linux man-pages project.  A  description  of  the
       project,     and    information    about    reporting    bugs,    can    be    found    at
       http://www.kernel.org/doc/man-pages/.



GNU                                         2012-01-18                                    GETS(3)