Commit | Line | Data |
---|---|---|
1ed3a85e WJ |
1 | .\" Copyright (c) 1990, 1991 The Regents of the University of California. |
2 | .\" All rights reserved. | |
3 | .\" | |
4 | .\" This code is derived from software contributed to Berkeley by | |
5 | .\" Chris Torek and the American National Standards Committee X3, | |
6 | .\" on Information Processing Systems. | |
7 | .\" | |
8 | .\" Redistribution and use in source and binary forms, with or without | |
9 | .\" modification, are permitted provided that the following conditions | |
10 | .\" are met: | |
11 | .\" 1. Redistributions of source code must retain the above copyright | |
12 | .\" notice, this list of conditions and the following disclaimer. | |
13 | .\" 2. Redistributions in binary form must reproduce the above copyright | |
14 | .\" notice, this list of conditions and the following disclaimer in the | |
15 | .\" documentation and/or other materials provided with the distribution. | |
16 | .\" 3. All advertising materials mentioning features or use of this software | |
17 | .\" must display the following acknowledgement: | |
18 | .\" This product includes software developed by the University of | |
19 | .\" California, Berkeley and its contributors. | |
20 | .\" 4. Neither the name of the University nor the names of its contributors | |
21 | .\" may be used to endorse or promote products derived from this software | |
22 | .\" without specific prior written permission. | |
23 | .\" | |
24 | .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
25 | .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
26 | .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
27 | .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
28 | .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
29 | .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
30 | .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
31 | .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
32 | .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
33 | .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
34 | .\" SUCH DAMAGE. | |
35 | .\" | |
36 | .\" @(#)fgets.3 6.9 (Berkeley) 6/29/91 | |
37 | .\" | |
38 | .Dd June 29, 1991 | |
39 | .Dt FGETS 3 | |
40 | .Os | |
41 | .Sh NAME | |
42 | .Nm fgets , | |
43 | .Nm gets | |
44 | .Nd get a line from a stream | |
45 | .Sh SYNOPSIS | |
46 | .Fd #include <stdio.h> | |
47 | .Ft char * | |
48 | .Fn fgets "char *str" "size_t size" "FILE *stream" | |
49 | .Ft char * | |
50 | .Fn gets "char *str" | |
51 | .Sh DESCRIPTION | |
52 | The | |
53 | .Fn fgets | |
54 | function | |
55 | reads at most one less than the number of characters specified by | |
56 | .Xr size | |
57 | from the given | |
58 | .Fa stream | |
59 | and stores them in the string | |
60 | .Fa str . | |
61 | Reading stops when a newline character is found, | |
62 | at end-of-file or error. | |
63 | The newline, if any, is retained. | |
64 | In any case a | |
65 | .Ql \e0 | |
66 | character is appended to end the string. | |
67 | .Pp | |
68 | The | |
69 | .Fn gets | |
70 | function | |
71 | is equivalent to | |
72 | .Fn fgets | |
73 | with an infinite | |
74 | .Xr size | |
75 | and a | |
76 | .Fa stream | |
77 | of | |
78 | .Em stdin , | |
79 | except that the newline character (if any) is not stored in the string. | |
80 | It is the caller's responsibility to ensure that the input line, | |
81 | if any, is sufficiently short to fit in the string. | |
82 | .Sh RETURN VALUES | |
83 | .Pp | |
84 | Upon successful completion, | |
85 | .Fn fgets | |
86 | and | |
87 | .Fn gets | |
88 | return | |
89 | a pointer to the string. | |
90 | If end-of-file or an error occurs before any characters are read, | |
91 | they return | |
92 | .Dv NULL. | |
93 | The | |
94 | .Fn fgets | |
95 | and | |
96 | functions | |
97 | .Fn gets | |
98 | do not distinguish between end-of-file and error, and callers must use | |
99 | .Xr feof 3 | |
100 | and | |
101 | .Xr ferror 3 | |
102 | to determine which occurred. | |
103 | .Sh ERRORS | |
104 | .Bl -tag -width [EBADF] | |
105 | .It Bq Er EBADF | |
106 | The given | |
107 | .Fa stream | |
108 | is not a readable stream. | |
109 | .El | |
110 | .Pp | |
111 | The function | |
112 | .Fn fgets | |
113 | may also fail and set | |
114 | .Va errno | |
115 | for any of the errors specified for the routines | |
116 | .Xr fflush 3 , | |
117 | .Xr fstat 2 , | |
118 | .Xr read 2 , | |
119 | or | |
120 | .Xr malloc 3 . | |
121 | .Pp | |
122 | The function | |
123 | .Fn gets | |
124 | may also fail and set | |
125 | .Va errno | |
126 | for any of the errors specified for the routine | |
127 | .Xr getchar 3 . | |
128 | .Sh SEE ALSO | |
129 | .Xr feof 3 , | |
130 | .Xr ferror 3 , | |
131 | .Xr fgetline 3 | |
132 | .Sh STANDARDS | |
133 | The functions | |
134 | .Fn fgets | |
135 | and | |
136 | .Fn gets | |
137 | conform to | |
138 | .St -ansiC . | |
139 | .Sh BUGS | |
140 | Since it is usually impossible to ensure that the next input line | |
141 | is less than some arbitrary length, and because overflowing the | |
142 | input buffer is almost invariably a security violation, programs | |
143 | should | |
144 | .Em NEVER | |
145 | use | |
146 | .Fn gets . | |
147 | The | |
148 | .Fn gets | |
149 | function | |
150 | exists purely to conform to | |
151 | .St -ansiC . |