1libc_db(3LIB) Interface Libraries libc_db(3LIB)
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6 libc_db - threads debugging library
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9 cc [ flag ... ] file ... -lc_db [ library ... ]
10 #include <proc_service.h>
11 #include <thread_db.h>
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15 The libc_db library provides support for monitoring and manipulating
16 threads-related aspects of a multithreaded program. There are at least
17 two processes involved, the controlling process and one or more target
18 processes. The controlling process is the libc_db client, which links
19 with libc_db and uses libc_db to inspect or modify threads-related
20 aspects of one or more target processes. The target processes must be
21 multithreaded processes that use libc. The controlling process mignt or
22 might not be multithreaded itself.
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25 The most commonly anticipated use for libc_db is that the controlling
26 process will be a debugger for a multithreaded program, hence the "db"
27 in libc_db.
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30 The libc_db library is dependent on the internal implementation details
31 of libc. It is a "friend" of libc in the C++ sense, which is precisely
32 the "value added" by libc_db. It encapsulates the knowledge of libc
33 internals that a debugger needs to manipulate the threads-related state
34 of a target process.
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37 To be able to inspect and manipulate target processes, libc_db makes
38 use of certain process control primitives that must be provided by the
39 process using libc_db. The imported interfaces are defined in proc_ser‐
40 vice(3PROC). In other words, the controlling process is linked with
41 libc_db and calls routines in libc_db. In turn, libc_db calls certain
42 routines that it expects the controlling process to provide. These
43 process control primitives allow libc_db to:
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45 o Look up symbols in a target process.
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47 o Stop and continue individual lightweight processes ( LWPs)
48 within a target process.
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50 o Stop and continue an entire target process.
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52 o Read and write memory and registers in a target process.
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55 Initially, a controlling process obtains a handle for a target process.
56 Through that handle it can then obtain handles for the component
57 objects of the target process, its threads, its synchronization
58 objects, and its thread-specific-data keys.
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61 When libc_db needs to return sets of handles to the controlling
62 process, for example, when returning handles for all the threads in a
63 target process, it uses an iterator function. An iterator function
64 calls back a client-specified function once for each handle to be
65 returned, passing one handle back on each call to the callback func‐
66 tion. The calling function also passes another parameter to the itera‐
67 tor function, which the iterator function passes on to the callback
68 function. This makes it easy to build a linked list of thread handles
69 for a particular target process. The additional parameter is the head
70 of the linked list, and the callback function simply inserts the cur‐
71 rent handle into the linked list.
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74 Callback functions are expected to return an integer. Iteration termi‐
75 nates early if a callback function returns a non-zero value. Otherwise,
76 iteration terminates when there are no more handles to pass back.
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79 The shared object libc_db.so.1 provides the public interfaces defined
80 below. See Intro(3) for additional information on shared object inter‐
81 faces.
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86 td_init td_log
87 td_sync_get_info td_sync_get_stats
88 td_sync_setstate td_sync_waiters
89 td_ta_clear_event td_ta_delete
90 td_ta_enable_stats td_ta_event_addr
91 td_ta_event_getmsg td_ta_get_nthreads
92 td_ta_get_ph td_ta_get_stats
93 td_ta_map_addr2sync td_ta_map_id2thr
94 td_ta_map_lwp2thr td_ta_new
95 td_ta_reset_stats td_ta_set_event
96 td_ta_setconcurrency td_ta_sync_iter
97 td_ta_sync_tracking_enable td_ta_thr_iter
98 td_ta_tsd_iter td_thr_clear_event
99 td_thr_dbresume td_thr_dbsuspend
100 td_thr_event_enable td_thr_event_getmsg
101 td_thr_get_info td_thr_getfpregs
102 td_thr_getgregs td_thr_getxregs
103 td_thr_getxregsize td_thr_lockowner
104 td_thr_set_event td_thr_setfpregs
105 td_thr_setgregs td_thr_setprio
106 td_thr_setsigpending td_thr_setxregs
107 td_thr_sigsetmask td_thr_sleepinfo
108 td_thr_tsd td_thr_validate
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112 /lib/libc_db.so.1 shared object
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115 /lib/64/libc_db.so.1 64-bit shared object
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119 See attributes(5) for description of the following attributes:
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124 ┌─────────────────────────────┬─────────────────────────────┐
125 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
126 ├─────────────────────────────┼─────────────────────────────┤
127 │Availability │SUNWcsl (32-bit) │
128 │ │SUNWcslx (64-bit) │
129 ├─────────────────────────────┼─────────────────────────────┤
130 │MT-Level │Safe │
131 └─────────────────────────────┴─────────────────────────────┘
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134 Intro(3), td_ta_new(3C_DB), attributes(5), threads(5)
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138SunOS 5.11 24 Mar 2004 libc_db(3LIB)