1GETS(3)                    Linux Programmer's Manual                   GETS(3)
2
3
4

NAME

6       fgetc,  fgets,  getc,  getchar,  gets, ungetc - input of characters and
7       strings
8

SYNOPSIS

10       #include <stdio.h>
11
12       int fgetc(FILE *stream);
13
14       char *fgets(char *s, int size, FILE *stream);
15
16       int getc(FILE *stream);
17
18       int getchar(void);
19
20       char *gets(char *s);
21
22       int ungetc(int c, FILE *stream);
23

DESCRIPTION

25       fgetc() reads the next character from  stream  and  returns  it  as  an
26       unsigned char cast to an int, or EOF on end of file or error.
27
28       getc()  is equivalent to fgetc() except that it may be implemented as a
29       macro which evaluates stream more than once.
30
31       getchar() is equivalent to getc(stdin).
32
33       gets() reads a line from stdin into the buffer pointed to  by  s  until
34       either  a  terminating newline or EOF, which it replaces with '\0'.  No
35       check for buffer overrun is performed (see BUGS below).
36
37       fgets() reads in at most one less than size characters from stream  and
38       stores  them  into  the buffer pointed to by s.  Reading stops after an
39       EOF or a newline.  If a newline is read, it is stored into the  buffer.
40       A '\0' is stored after the last character in the buffer.
41
42       ungetc()  pushes  c  back to stream, cast to unsigned char, where it is
43       available for subsequent read operations.  Pushed-back characters  will
44       be returned in reverse order; only one pushback is guaranteed.
45
46       Calls  to the functions described here can be mixed with each other and
47       with calls to other input functions from the stdio library for the same
48       input stream.
49
50       For nonlocking counterparts, see unlocked_stdio(3).
51

RETURN VALUE

53       fgetc(),  getc() and getchar() return the character read as an unsigned
54       char cast to an int or EOF on end of file or error.
55
56       gets() and fgets() return s on success, and NULL on error or  when  end
57       of file occurs while no characters have been read.
58
59       ungetc() returns c on success, or EOF on error.
60

CONFORMING TO

62       C89,  C99,  POSIX.1-2001.  LSB deprecates gets().  POSIX.1-2008 removes
63       the specification of gets().
64

BUGS

66       Never use gets().  Because it is impossible to tell without knowing the
67       data  in  advance  how  many  characters  gets() will read, and because
68       gets() will continue to store characters past the end of the buffer, it
69       is  extremely  dangerous  to  use.   It has been used to break computer
70       security.  Use fgets() instead.
71
72       It is not advisable to mix calls to  input  functions  from  the  stdio
73       library with low-level calls to read(2) for the file descriptor associ‐
74       ated with the input stream; the results  will  be  undefined  and  very
75       probably not what you want.
76

SEE ALSO

78       read(2), write(2), ferror(3), fgetwc(3), fgetws(3), fopen(3), fread(3),
79       fseek(3),  getline(3),  getwchar(3),  puts(3),  scanf(3),   ungetwc(3),
80       unlocked_stdio(3)
81

COLOPHON

83       This  page  is  part of release 3.25 of the Linux man-pages project.  A
84       description of the project, and information about reporting  bugs,  can
85       be found at http://www.kernel.org/doc/man-pages/.
86
87
88
89GNU                               2008-08-06                           GETS(3)
Impressum