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1 .\" Copyright (C) 2001 Andries Brouwer <aeb@cwi.nl>.
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24 .\"
25 .TH UNLOCKED_STDIO 3 2021-03-22 "" "Linux Programmer's Manual"
26 .SH NAME
27 getc_unlocked, getchar_unlocked, putc_unlocked,
28 putchar_unlocked \- nonlocking stdio functions
29 .SH SYNOPSIS
30 .nf
31 .B #include <stdio.h>
32 .PP
33 .BI "int getc_unlocked(FILE *" stream );
34 .B "int getchar_unlocked(void);"
35 .BI "int putc_unlocked(int " c ", FILE *" stream );
36 .BI "int putchar_unlocked(int " c );
37 .PP
38 .BI "void clearerr_unlocked(FILE *" stream );
39 .BI "int feof_unlocked(FILE *" stream );
40 .BI "int ferror_unlocked(FILE *" stream );
41 .BI "int fileno_unlocked(FILE *" stream );
42 .BI "int fflush_unlocked(FILE *" stream );
43 .PP
44 .BI "int fgetc_unlocked(FILE *" stream );
45 .BI "int fputc_unlocked(int " c ", FILE *" stream );
46 .PP
47 .BI "size_t fread_unlocked(void *restrict " ptr ", size_t " size ", size_t " n ,
48 .BI " FILE *restrict " stream );
49 .BI "size_t fwrite_unlocked(const void *restrict " ptr ", size_t " size \
50 ", size_t " n ,
51 .BI " FILE *restrict " stream );
52 .PP
53 .BI "char *fgets_unlocked(char *restrict " s ", int " n \
54 ", FILE *restrict " stream );
55 .BI "int fputs_unlocked(const char *restrict " s ", FILE *restrict " stream );
56 .PP
57 .B #include <wchar.h>
58 .PP
59 .BI "wint_t getwc_unlocked(FILE *" stream );
60 .B "wint_t getwchar_unlocked(void);"
61 .BI "wint_t fgetwc_unlocked(FILE *" stream );
62 .PP
63 .BI "wint_t fputwc_unlocked(wchar_t " wc ", FILE *" stream );
64 .BI "wint_t putwc_unlocked(wchar_t " wc ", FILE *" stream );
65 .BI "wint_t putwchar_unlocked(wchar_t " wc );
66 .PP
67 .BI "wchar_t *fgetws_unlocked(wchar_t *restrict " ws ", int " n ,
68 .BI " FILE *restrict " stream );
69 .BI "int fputws_unlocked(const wchar_t *restrict " ws ,
70 .BI " FILE *restrict " stream );
71 .fi
72 .PP
73 .RS -4
74 Feature Test Macro Requirements for glibc (see
75 .BR feature_test_macros (7)):
76 .nh
77 .RE
78 .ad l
79 .PP
80 .BR getc_unlocked (),
81 .BR getchar_unlocked (),
82 .BR putc_unlocked (),
83 .BR putchar_unlocked ():
84 .nf
85 /* Since glibc 2.24: */ _POSIX_C_SOURCE >= 199309L
86 || /* Glibc <= 2.23: */ _POSIX_C_SOURCE
87 || /* Glibc <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE
88 .fi
89 .PP
90 .BR clearerr_unlocked (),
91 .BR feof_unlocked (),
92 .BR ferror_unlocked (),
93 .BR fileno_unlocked (),
94 .BR fflush_unlocked (),
95 .BR fgetc_unlocked (),
96 .BR fputc_unlocked (),
97 .BR fread_unlocked (),
98 .BR fwrite_unlocked ():
99 .nf
100 /* Glibc since 2.19: */ _DEFAULT_SOURCE
101 || /* Glibc <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE
102 .fi
103 .PP
104 .BR fgets_unlocked (),
105 .BR fputs_unlocked (),
106 .BR getwc_unlocked (),
107 .BR getwchar_unlocked (),
108 .BR fgetwc_unlocked (),
109 .BR fputwc_unlocked (),
110 .BR putwchar_unlocked (),
111 .BR fgetws_unlocked (),
112 .BR fputws_unlocked ():
113 .nf
114 _GNU_SOURCE
115 .fi
116 .hy
117 .ad
118 .SH DESCRIPTION
119 Each of these functions has the same behavior as its counterpart
120 without the "_unlocked" suffix, except that they do not use locking
121 (they do not set locks themselves, and do not test for the presence
122 of locks set by others) and hence are thread-unsafe.
123 See
124 .BR flockfile (3).
125 .SH ATTRIBUTES
126 For an explanation of the terms used in this section, see
127 .BR attributes (7).
128 .ad l
129 .nh
130 .TS
131 allbox;
132 lb lb lbx
133 l l l.
134 Interface Attribute Value
135 T{
136 .BR getc_unlocked (),
137 .BR putc_unlocked (),
138 .BR clearerr_unlocked (),
139 .BR fflush_unlocked (),
140 .BR fgetc_unlocked (),
141 .BR fputc_unlocked (),
142 .BR fread_unlocked (),
143 .BR fwrite_unlocked (),
144 .BR fgets_unlocked (),
145 .BR fputs_unlocked (),
146 .BR getwc_unlocked (),
147 .BR fgetwc_unlocked (),
148 .BR fputwc_unlocked (),
149 .BR putwc_unlocked (),
150 .BR fgetws_unlocked (),
151 .BR fputws_unlocked ()
152 T} Thread safety T{
153 MT-Safe race:stream
154 T}
155 T{
156 .BR getchar_unlocked (),
157 .BR getwchar_unlocked ()
158 T} Thread safety T{
159 MT-Unsafe race:stdin
160 T}
161 T{
162 .BR putchar_unlocked (),
163 .BR putwchar_unlocked ()
164 T} Thread safety T{
165 MT-Unsafe race:stdout
166 T}
167 T{
168 .BR feof_unlocked (),
169 .BR ferror_unlocked (),
170 .BR fileno_unlocked ()
171 T} Thread safety MT-Safe
172 .TE
173 .hy
174 .ad
175 .sp 1
176 .SH CONFORMING TO
177 The four functions
178 .BR getc_unlocked (),
179 .BR getchar_unlocked (),
180 .BR putc_unlocked (),
181 .BR putchar_unlocked ()
182 are in POSIX.1-2001 and POSIX.1-2008.
183 .PP
184 The nonstandard
185 .BR *_unlocked ()
186 variants occur on a few UNIX systems, and are available in recent glibc.
187 .\" E.g., in HP-UX 10.0. In HP-UX 10.30 they are called obsolescent, and
188 .\" moved to a compatibility library.
189 .\" Available in HP-UX 10.0: clearerr_unlocked, fclose_unlocked,
190 .\" feof_unlocked, ferror_unlocked, fflush_unlocked, fgets_unlocked,
191 .\" fgetwc_unlocked, fgetws_unlocked, fileno_unlocked, fputs_unlocked,
192 .\" fputwc_unlocked, fputws_unlocked, fread_unlocked, fseek_unlocked,
193 .\" ftell_unlocked, fwrite_unlocked, getc_unlocked, getchar_unlocked,
194 .\" getw_unlocked, getwc_unlocked, getwchar_unlocked, putc_unlocked,
195 .\" putchar_unlocked, puts_unlocked, putws_unlocked, putw_unlocked,
196 .\" putwc_unlocked, putwchar_unlocked, rewind_unlocked, setvbuf_unlocked,
197 .\" ungetc_unlocked, ungetwc_unlocked.
198 They should probably not be used.
199 .SH SEE ALSO
200 .BR flockfile (3),
201 .BR stdio (3)