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1 perry 1 !!NAME
2 fgetc, fgets, getc, getchar, gets, ungetc - input of characters and strings
3 !!SYNOPSIS
4
2 SamJansen 5 __#include <stdio.h>__
6
7 __int fgetc(FILE *__''stream''__);__
8 __char *fgets(char *__''s''__, int__ ''size''__, FILE *__''stream''__);__
9 __int getc(FILE *__''stream''__);__
10 __int getchar(void);__
11 __char *gets(char *__''s''__);__
12 __int ungetc(int__ ''c''__, FILE *__''stream''__);__
1 perry 13
14 !!DESCRIPTION
15
16
17 __fgetc()__ reads the next character from ''stream''
18 and returns it as an __unsigned char__ cast to an
19 __int__, or __EOF__ on end of file or
20 error.
21
22
23 __getc()__ is equivalent to __fgetc()__ except that it
24 may be implemented as a macro which evaluates ''stream''
25 more than once.
26
27
28 __getchar()__ is equivalent to
29 __getc(__''stdin''__)__.
30
31
32 __gets()__ reads a line from ''stdin'' into the buffer
33 pointed to by ''s'' until either a terminating newline or
34 __EOF__, which it replaces with __'0'__. No check for
35 buffer overrun is performed (see __BUGS__
36 below).
37
38
39 __fgets()__ reads in at most one less than ''size''
40 characters from ''stream'' and stores them into the
41 buffer pointed to by ''s''. Reading stops after an
42 __EOF__ or a newline. If a newline is read, it is stored
43 into the buffer. A __'0'__ is stored after the last
44 character in the buffer.
45
46
47 __ungetc()__ pushes ''c'' back to ''stream'', cast
48 to __unsigned char__, where it is available for
49 subsequent read operations. Pushed - back characters will be
50 returned in reverse order; only one pushback is
51 guaranteed.
52
53
54 Calls to the functions described here can be mixed with each
55 other and with calls to other input functions from the
56 __stdio__ library for the same input stream.
57 !!RETURN VALUE
58
59
60 __fgetc()__, __getc()__ and __getchar()__ return
61 the character read as an __unsigned char__ cast to an
62 __int__ or __EOF__ on end of file or
63 error.
64
65
66 __gets()__ and __fgets()__ return ''s'' on success,
67 and __NULL__ on error or when end of file occurs while no
68 characters have been read.
69
70
71 __ungetc()__ returns ''c'' on success, or __EOF__
72 on error.
73 !!CONFORMING TO
74
75
3 JohnMcPherson 76 [ANSI] - C, [POSIX].1
1 perry 77 !!BUGS
78
79
80 Never use __gets()__. Because it is impossible to tell
81 without knowing the data in advance how many characters
82 __gets()__ will read, and because __gets()__ will
83 continue to store characters past the end of the buffer, it
84 is extremely dangerous to use. It has been used to break
85 computer security. Use __fgets()__ instead.
86
87
88 It is not advisable to mix calls to input functions from the
89 __stdio__ library with low - level calls to __read()__
90 for the file descriptor associated with the input stream;
91 the results will be undefined and very probably not what you
92 want.
93 !!SEE ALSO
94
95
96 read(2), write(2), fopen(3),
97 fread(3), scanf(3), puts(3),
98 fseek(3), ferror(3)
99 ----
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