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1 | .\" Copyright (c) 1990, 1991, 1993 |
2 | .\" The Regents of the University of California. All rights reserved. | |
74188ac6 | 3 | .\" |
411867e7 | 4 | .\" This code is derived from software contributed to Berkeley by |
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5 | .\" Chris Torek and the American National Standards Committee X3, |
6 | .\" on Information Processing Systems. | |
74188ac6 | 7 | .\" |
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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. | |
411867e7 | 35 | .\" |
ed554bc5 | 36 | .\" @(#)fread.3 8.2 (Berkeley) 3/8/94 |
ad787160 | 37 | .\" |
ed554bc5 | 38 | .Dd March 8, 1994 |
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39 | .Dt FREAD 3 |
40 | .Os | |
41 | .Sh NAME | |
42 | .Nm fread , | |
43 | .Nm fwrite | |
44 | .Nd binary stream input/output | |
45 | .Sh SYNOPSIS | |
46 | .Fd #include <stdio.h> | |
47 | .Ft int | |
48 | .Fn fread "void *ptr" "size_t size" "size_t nmemb" "FILE *stream" | |
49 | .Ft int | |
be9fd4cc | 50 | .Fn fwrite "const void *ptr" "size_t size" "size_t nmemb" "FILE *stream" |
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51 | .Sh DESCRIPTION |
52 | The function | |
53 | .Fn fread | |
411867e7 | 54 | reads |
ae59e04c | 55 | .Fa nmemb |
911c9ce6 | 56 | objects, each |
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57 | .Xr size |
58 | bytes long, from the stream pointed to by | |
59 | .Fa stream , | |
411867e7 | 60 | storing them at the location given by |
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61 | .Fa ptr . |
62 | .Pp | |
63 | The function | |
64 | .Fn fwrite | |
65 | writes | |
66 | .Fa nmemb | |
911c9ce6 | 67 | objects, each |
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68 | .Fa size |
69 | bytes long, to the stream pointed to by | |
70 | .Fa stream , | |
71 | obtaining them from the location given by | |
72 | .Fa ptr . | |
73 | .Sh RETURN VALUES | |
74 | The functions | |
75 | .Fn fread | |
76 | and | |
77 | .Fn fwrite | |
78 | advance the file position indicator for the stream | |
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79 | by the number of bytes read or written. |
80 | They return the number of objects read or written. | |
ae59e04c | 81 | If an error occurs, or the end-of-file is reached, |
911c9ce6 | 82 | the return value is a short object count (or zero). |
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83 | .Pp |
84 | The function | |
85 | .Fn fread | |
86 | does not distinguish between end-of-file and error, and callers | |
1382c0b2 | 87 | must use |
ae59e04c | 88 | .Xr feof 3 |
1382c0b2 | 89 | and |
ae59e04c | 90 | .Xr ferror 3 |
1382c0b2 | 91 | to determine which occurred. |
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92 | The function |
93 | .Fn fwrite | |
94 | returns a value less than | |
95 | .Fa nmemb | |
96 | only if a write error has occurred. | |
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97 | .Sh SEE ALSO |
98 | .Xr read 2 , | |
99 | .Xr write 2 | |
100 | .Sh STANDARDS | |
101 | The functions | |
102 | .Fn fread | |
74188ac6 | 103 | and |
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104 | .Fn fwrite |
105 | conform to | |
106 | .St -ansiC . |