ungetc

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

    NAME
           fgetc, fgets, getc, getchar, gets, ungetc - input of char-
           acters 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 evaluates 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  per-
           formed (see BUGS below).

           fgets()  reads  in at most one less than n 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 buffer.

           ungetc()  pushes  c back to stream, cast to unsigned char,
           where it is  available  for  subsequent  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.

    RETURN VALUES
           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 end of
           file or error.

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

    GNU                       April 4, 1993                         1

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

    CONFORMS TO
           ANSI - C, POSIX.1

    BUGS
           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() for the
           file descriptor associated  with  the  input  stream;  the
           results  will  be undefined and very probably not what you
           want.

### SEE ALSO

read, write, fopen, fread, scanf, puts, fseek, ferror,

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    GNU                       April 4, 1993                         2

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