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1 | .\" Copyright (c) 2017, Michael Kerrisk <mtk.manpages@gmail.com> |
2 | .\" | |
3 | .\" %%%LICENSE_START(VERBATIM) | |
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24 | .\" | |
25 | .TH PTHREAD_SPIN_LOCK 3 2017-09-30 "Linux" "Linux Programmer's Manual" | |
26 | .SH NAME | |
27 | pthread_spin_lock, pthread_spin_trylock, pthread_spin_unlock \- | |
28 | lock and unlock a spin lock | |
29 | .SH SYNOPSIS | |
30 | .nf | |
31 | .B #include <pthread.h> | |
32 | .PP | |
33 | .BI "int pthread_spin_lock(pthread_spinlock_t *" lock ); | |
34 | .BI "int pthread_spin_trylock(pthread_spinlock_t *" lock ); | |
35 | .BI "int pthread_spin_unlock(pthread_spinlock_t *" lock ); | |
36 | .fi | |
37 | .PP | |
38 | Compile and link with \fI\-pthread\fP. | |
39 | .PP | |
40 | .in -4n | |
41 | Feature Test Macro Requirements for glibc (see | |
42 | .BR feature_test_macros (7)): | |
43 | .in | |
44 | .PP | |
45 | .BR pthread_spin_lock (), | |
46 | .BR pthread_spin_trylock (): | |
47 | .br | |
48 | .RS 4 | |
49 | .ad l | |
50 | _POSIX_C_SOURCE >= 200112L | |
51 | .RE | |
52 | .ad | |
53 | .SH DESCRIPTION | |
54 | The | |
55 | .BR pthread_spin_lock () | |
56 | function locks the spin lock referred to by | |
57 | .IR lock . | |
58 | If the spin lock is currently unlocked, | |
59 | the calling thread acquires the lock immediately. | |
60 | If the spin lock is currently locked by another thread, | |
61 | the calling thread spins, testing the lock until it becomes available, | |
62 | at which point the calling thread acquires the lock. | |
63 | .PP | |
64 | Calling | |
65 | .BR pthread_spin_lock () | |
66 | on a lock that is already held by the caller results in undefined behavior. | |
67 | .PP | |
68 | The | |
69 | .BR pthread_spin_trylock () | |
70 | function is like | |
71 | .BR pthread_spin_lock (), | |
72 | except that if the spin lock referred to by | |
73 | .I lock | |
74 | is currently locked, | |
75 | then, instead of spinning, the call returns immediately with the error | |
76 | .BR EBUSY . | |
77 | .PP | |
78 | The | |
79 | .BR pthread_spin_unlock () | |
80 | function unlocks the spin lock referred to | |
81 | .IR lock . | |
82 | If any threads are spinning on the lock, | |
83 | one of those threads will then acquire the lock. | |
84 | .PP | |
85 | Calling | |
86 | .BR pthread_spin_unlock () | |
87 | on a lock that is not held by the caller results in undefined behavior. | |
88 | .SH RETURN VALUE | |
89 | On success, there functions return zero. | |
90 | On failure, they return an error number. | |
91 | .SH ERRORS | |
92 | .BR pthread_spin_lock () | |
93 | may fail with the following errors: | |
94 | .TP | |
95 | .B EDEADLOCK | |
96 | .\" Not detected in glibc | |
97 | The system detected a deadlock condition. | |
98 | .PP | |
99 | .BR pthread_spin_trylock () | |
100 | can fail with the following errors: | |
101 | .TP | |
102 | .B EBUSY | |
103 | The spin lock is currently locked by another thread. | |
104 | .SH VERSIONS | |
105 | These functions first appeared in glibc in version 2.2. | |
106 | .SH CONFORMING TO | |
107 | POSIX.1-2001. | |
108 | .SH NOTES | |
109 | Applying any of the functions described on this page to | |
110 | an uninitialized spin lock results in undefined behavior. | |
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111 | .PP |
112 | Carefully read NOTES in | |
113 | .BR pthread_spin_init (3). | |
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114 | .SH SEE ALSO |
115 | .ad l | |
116 | .nh | |
117 | .\" FIXME . .BR pthread_mutex_lock (3), | |
118 | .BR pthread_spin_destroy (3), | |
119 | .BR pthread_spin_init (3), | |
120 | .BR pthreads (7) |