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a1eaacb1 | 1 | '\" t |
5df98ea9 | 2 | .\" Copyright (C) 2012 Chandan Apsangi <chandan.jc@gmail.com> |
7d928e0d | 3 | .\" and Copyright (C) 2013 Michael Kerrisk <mtk.manpages@gmail.com> |
5df98ea9 | 4 | .\" |
5fbde956 | 5 | .\" SPDX-License-Identifier: Linux-man-pages-copyleft |
5df98ea9 | 6 | .\" |
4c1c5274 | 7 | .TH pthread_setname_np 3 (date) "Linux man-pages (unreleased)" |
5df98ea9 MK |
8 | .SH NAME |
9 | pthread_setname_np, pthread_getname_np \- set/get the name of a thread | |
1cefd9b1 AC |
10 | .SH LIBRARY |
11 | POSIX threads library | |
8fc3b2cf | 12 | .RI ( libpthread ", " \-lpthread ) |
5df98ea9 MK |
13 | .SH SYNOPSIS |
14 | .nf | |
15 | .BR "#define _GNU_SOURCE" " /* See feature_test_macros(7) */" | |
16 | .B #include <pthread.h> | |
c6d039a3 | 17 | .P |
9bfc9cb1 | 18 | .BI "int pthread_setname_np(pthread_t " thread ", const char *" name ); |
1eed67e7 AC |
19 | .BI "int pthread_getname_np(pthread_t " thread ", char " name [. size "], \ |
20 | size_t " size ); | |
5df98ea9 | 21 | .fi |
5df98ea9 MK |
22 | .SH DESCRIPTION |
23 | By default, all the threads created using | |
e4a83b01 | 24 | .BR pthread_create () |
5df98ea9 | 25 | inherit the program name. |
e4a83b01 MK |
26 | The |
27 | .BR pthread_setname_np () | |
f1a5fff8 | 28 | function can be used to set a unique name for a thread, |
e4a83b01 | 29 | which can be useful for debugging |
ce0234ff | 30 | multithreaded applications. |
d6c1998e AC |
31 | The thread name is a meaningful C language string, |
32 | whose length is restricted to 16 characters, | |
33 | including the terminating null byte (\[aq]\e0\[aq]). | |
6350e974 MK |
34 | The |
35 | .I thread | |
36 | argument specifies the thread whose name is to be changed; | |
37 | .I name | |
38 | specifies the new name. | |
c6d039a3 | 39 | .P |
5df98ea9 | 40 | The |
e4a83b01 MK |
41 | .BR pthread_getname_np () |
42 | function can be used to retrieve the name of the thread. | |
6350e974 MK |
43 | The |
44 | .I thread | |
3fd9346e | 45 | argument specifies the thread whose name is to be retrieved. |
6350e974 MK |
46 | The buffer |
47 | .I name | |
48 | is used to return the thread name; | |
8c54e23e | 49 | .I size |
6350e974 MK |
50 | specifies the number of bytes available in |
51 | .IR name . | |
e4a83b01 MK |
52 | The buffer specified by |
53 | .I name | |
6350e974 | 54 | should be at least 16 characters in length. |
5df98ea9 MK |
55 | The returned thread name in the output buffer will be null terminated. |
56 | .SH RETURN VALUE | |
57 | On success, these functions return 0; | |
58 | on error, they return a nonzero error number. | |
59 | .SH ERRORS | |
eb6c2cc6 MK |
60 | The |
61 | .BR pthread_setname_np () | |
4a2403ed | 62 | function can fail with the following error: |
5df98ea9 MK |
63 | .TP |
64 | .B ERANGE | |
e4a83b01 MK |
65 | The length of the string specified pointed to by |
66 | .I name | |
67 | exceeds the allowed limit. | |
c6d039a3 | 68 | .P |
4a2403ed MK |
69 | The |
70 | .BR pthread_getname_np () | |
71 | function can fail with the following error: | |
72 | .TP | |
73 | .B ERANGE | |
74 | The buffer specified by | |
75 | .I name | |
76 | and | |
8c54e23e | 77 | .I size |
4a2403ed | 78 | is too small to hold the thread name. |
c6d039a3 | 79 | .P |
e4a83b01 | 80 | If either of these functions fails to open |
0d782b8d | 81 | .IR /proc/self/task/ tid /comm , |
e4a83b01 MK |
82 | then the call may fail with one of the errors described in |
83 | .BR open (2). | |
412793f9 ZL |
84 | .SH ATTRIBUTES |
85 | For an explanation of the terms used in this section, see | |
86 | .BR attributes (7). | |
87 | .TS | |
88 | allbox; | |
c466875e | 89 | lbx lb lb |
412793f9 ZL |
90 | l l l. |
91 | Interface Attribute Value | |
92 | T{ | |
9e54434e BR |
93 | .na |
94 | .nh | |
412793f9 ZL |
95 | .BR pthread_setname_np (), |
96 | .BR pthread_getname_np () | |
97 | T} Thread safety MT-Safe | |
98 | .TE | |
3113c7f3 | 99 | .SH STANDARDS |
4131356c | 100 | GNU; |
3ceb0d18 | 101 | hence the suffix "_np" (nonportable) in the names. |
4131356c AC |
102 | .SH HISTORY |
103 | glibc 2.12. | |
5df98ea9 | 104 | .SH NOTES |
e4a83b01 | 105 | .BR pthread_setname_np () |
f2cc5c88 | 106 | internally writes to the thread-specific |
7d4d1f8a | 107 | .I comm |
f2cc5c88 | 108 | file under the |
1ae6b2c7 | 109 | .I /proc |
5df98ea9 | 110 | filesystem: |
0d782b8d | 111 | .IR /proc/self/task/ tid /comm . |
e4a83b01 | 112 | .BR pthread_getname_np () |
3fd9346e | 113 | retrieves it from the same location. |
a14af333 | 114 | .SH EXAMPLES |
5df98ea9 | 115 | The program below demonstrates the use of |
e4a83b01 MK |
116 | .BR pthread_setname_np () |
117 | and | |
5df98ea9 | 118 | .BR pthread_getname_np (). |
c6d039a3 | 119 | .P |
5df98ea9 | 120 | The following shell session shows a sample run of the program: |
c6d039a3 | 121 | .P |
5df98ea9 | 122 | .in +4n |
e646a1ba | 123 | .EX |
e4a83b01 | 124 | .RB "$" " ./a.out" |
5df98ea9 MK |
125 | Created a thread. Default name is: a.out |
126 | The thread name after setting it is THREADFOO. | |
a1e9245d | 127 | \fB\[ha]Z\fP # Suspend the program |
6cfa298b | 128 | [1]+ Stopped ./a.out |
b957f81f | 129 | .RB "$ " "ps H \-C a.out \-o \[aq]pid tid cmd comm\[aq]" |
6cfa298b MK |
130 | PID TID CMD COMMAND |
131 | 5990 5990 ./a.out a.out | |
132 | 5990 5991 ./a.out THREADFOO | |
133 | .RB "$ " "cat /proc/5990/task/5990/comm" | |
134 | a.out | |
135 | .RB "$ " "cat /proc/5990/task/5991/comm" | |
136 | THREADFOO | |
b8302363 | 137 | .EE |
5df98ea9 | 138 | .in |
5df98ea9 MK |
139 | .SS Program source |
140 | \& | |
b0b6ab4e | 141 | .\" SRC BEGIN (pthread_setname_np.c) |
e7d0bb47 | 142 | .EX |
5df98ea9 | 143 | #define _GNU_SOURCE |
5a5208c1 | 144 | #include <err.h> |
ad3868f0 | 145 | #include <errno.h> |
5df98ea9 MK |
146 | #include <pthread.h> |
147 | #include <stdio.h> | |
ad3868f0 | 148 | #include <stdlib.h> |
5df98ea9 MK |
149 | #include <string.h> |
150 | #include <unistd.h> | |
fe5dba13 | 151 | \& |
5df98ea9 | 152 | #define NAMELEN 16 |
fe5dba13 | 153 | \& |
30a87638 MK |
154 | static void * |
155 | threadfunc(void *parm) | |
5df98ea9 | 156 | { |
b615a97e | 157 | sleep(5); // allow main program to set the thread name |
5df98ea9 MK |
158 | return NULL; |
159 | } | |
fe5dba13 | 160 | \& |
30a87638 | 161 | int |
aa1f53cc | 162 | main(int argc, char *argv[]) |
5df98ea9 MK |
163 | { |
164 | pthread_t thread; | |
165 | int rc; | |
166 | char thread_name[NAMELEN]; | |
fe5dba13 | 167 | \& |
5df98ea9 | 168 | rc = pthread_create(&thread, NULL, threadfunc, NULL); |
b615a97e | 169 | if (rc != 0) |
5a5208c1 | 170 | errc(EXIT_FAILURE, rc, "pthread_create"); |
fe5dba13 | 171 | \& |
5df98ea9 | 172 | rc = pthread_getname_np(thread, thread_name, NAMELEN); |
b615a97e | 173 | if (rc != 0) |
5a5208c1 | 174 | errc(EXIT_FAILURE, rc, "pthread_getname_np"); |
fe5dba13 | 175 | \& |
d1a71985 | 176 | printf("Created a thread. Default name is: %s\en", thread_name); |
e49d4430 | 177 | rc = pthread_setname_np(thread, (argc > 1) ? argv[1] : "THREADFOO"); |
b615a97e | 178 | if (rc != 0) |
5a5208c1 | 179 | errc(EXIT_FAILURE, rc, "pthread_setname_np"); |
fe5dba13 | 180 | \& |
5df98ea9 | 181 | sleep(2); |
fe5dba13 | 182 | \& |
44a16bcb | 183 | rc = pthread_getname_np(thread, thread_name, NAMELEN); |
b615a97e | 184 | if (rc != 0) |
5a5208c1 | 185 | errc(EXIT_FAILURE, rc, "pthread_getname_np"); |
d1a71985 | 186 | printf("The thread name after setting it is %s.\en", thread_name); |
fe5dba13 | 187 | \& |
5df98ea9 | 188 | rc = pthread_join(thread, NULL); |
b615a97e | 189 | if (rc != 0) |
5a5208c1 | 190 | errc(EXIT_FAILURE, rc, "pthread_join"); |
fe5dba13 | 191 | \& |
d1a71985 | 192 | printf("Done\en"); |
5df98ea9 MK |
193 | exit(EXIT_SUCCESS); |
194 | } | |
e7d0bb47 | 195 | .EE |
b0b6ab4e | 196 | .\" SRC END |
5df98ea9 MK |
197 | .SH SEE ALSO |
198 | .ad l | |
199 | .nh | |
200 | .BR prctl (2), | |
201 | .BR pthread_create (3), | |
202 | .BR pthreads (7) |