xref: /illumos-gate/usr/src/man/man3c/ferror.3c (revision cd62a92d4a964bfe61d35ba2301b69e65e22a509)
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18.\" Copyright 1989 AT&T
19.\" Copyright (c) 2005, Sun Microsystems, Inc.  All Rights Reserved
20.\" Copyright 2020 Robert Mustacchi
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22.Dd "March 25, 2020"
23.Dt FERROR 3C
24.Os
25.Sh NAME
26.Nm ferror ,
27.Nm feof ,
28.Nm clearerr ,
29.Nm fileno
30.Nd stream status inquiries
31.Sh SYNOPSIS
32.In stdio.h
33.Ft int
34.Fo ferror
35.Fa "FILE *stream"
36.Fc
37.Ft int
38.Fo feof
39.Fa "FILE *stream"
40.Fc
41.Ft void
42.Fo clearerr
43.Fa "FILE *stream"
44.Fc
45.Ft int
46.Fo fileno
47.Fa "FILE *stream"
48.Fc
49.Sh DESCRIPTION
50The
51.Fn ferror
52function returns a non-zero value when an error has
53previously occurred reading from or writing to the named
54.Fa stream
55.Po
56see
57.Xr Intro 3
58.Pc .
59It returns
60.Sy 0
61otherwise.
62.Pp
63The
64.Fn feof
65function returns a non-zero value when
66.Sy EOF
67has previously been detected reading the named input
68.Fa stream .
69It returns
70.Sy 0
71otherwise.
72.Pp
73The
74.Fn clearerr
75function resets the error indicator and
76.Sy EOF
77indicator to 0 on the named
78.Fa stream .
79.Pp
80The
81.Fn fileno
82function returns the integer file descriptor associated with
83the named
84.Fa stream ;
85see
86.Xr open 2 .
87Streams that are not associated with a file descriptor such as those
88that were created through the
89.Xr fmemopen 3C
90or
91.Xr open_memstream 3C
92functions will return
93.Sy -1 .
94.Sh INTERFACE STABILITY
95.Sy Standard
96.Sh MT-LEVEL
97.Sy MT-Safe
98.Sh SEE ALSO
99.Xr Intro 2 ,
100.Xr open 2 ,
101.Xr fmemopen 3C ,
102.Xr fopen 3C ,
103.Xr open_memstream 3C ,
104.Xr stdio 3C
105