1// Copyright (c) 2005, Google Inc.
2// All rights reserved.
3//
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5// modification, are permitted provided that the following conditions are
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7//
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9// notice, this list of conditions and the following disclaimer.
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13// distribution.
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17//
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28// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29
30// ---
31// Author: Sanjay Ghemawat
32//
33// Routines to extract the current stack trace.  These functions are
34// thread-safe.
35
36#ifndef GOOGLE_STACKTRACE_H_
37#define GOOGLE_STACKTRACE_H_
38
39// Annoying stuff for windows -- makes sure clients can import these functions
40#ifndef PERFTOOLS_DLL_DECL
41# ifdef _WIN32
42#   define PERFTOOLS_DLL_DECL  __declspec(dllimport)
43# else
44#   define PERFTOOLS_DLL_DECL
45# endif
46#endif
47
48
49// Skips the most recent "skip_count" stack frames (also skips the
50// frame generated for the "GetStackFrames" routine itself), and then
51// records the pc values for up to the next "max_depth" frames in
52// "result", and the corresponding stack frame sizes in "sizes".
53// Returns the number of values recorded in "result"/"sizes".
54//
55// Example:
56//      main() { foo(); }
57//      foo() { bar(); }
58//      bar() {
59//        void* result[10];
60//        int sizes[10];
61//        int depth = GetStackFrames(result, sizes, 10, 1);
62//      }
63//
64// The GetStackFrames call will skip the frame for "bar".  It will
65// return 2 and will produce pc values that map to the following
66// procedures:
67//      result[0]       foo
68//      result[1]       main
69// (Actually, there may be a few more entries after "main" to account for
70// startup procedures.)
71// And corresponding stack frame sizes will also be recorded:
72//    sizes[0]       16
73//    sizes[1]       16
74// (Stack frame sizes of 16 above are just for illustration purposes.)
75// Stack frame sizes of 0 or less indicate that those frame sizes couldn't
76// be identified.
77//
78// This routine may return fewer stack frame entries than are
79// available. Also note that "result" and "sizes" must both be non-NULL.
80extern PERFTOOLS_DLL_DECL int GetStackFrames(void** result, int* sizes, int max_depth,
81                          int skip_count);
82
83// Same as above, but to be used from a signal handler. The "uc" parameter
84// should be the pointer to ucontext_t which was passed as the 3rd parameter
85// to sa_sigaction signal handler. It may help the unwinder to get a
86// better stack trace under certain conditions. The "uc" may safely be NULL.
87extern PERFTOOLS_DLL_DECL int GetStackFramesWithContext(void** result, int* sizes, int max_depth,
88                                     int skip_count, const void *uc);
89
90// This is similar to the GetStackFrames routine, except that it returns
91// the stack trace only, and not the stack frame sizes as well.
92// Example:
93//      main() { foo(); }
94//      foo() { bar(); }
95//      bar() {
96//        void* result[10];
97//        int depth = GetStackTrace(result, 10, 1);
98//      }
99//
100// This produces:
101//      result[0]       foo
102//      result[1]       main
103//           ....       ...
104//
105// "result" must not be NULL.
106extern PERFTOOLS_DLL_DECL int GetStackTrace(void** result, int max_depth,
107                                            int skip_count);
108
109// Same as above, but to be used from a signal handler. The "uc" parameter
110// should be the pointer to ucontext_t which was passed as the 3rd parameter
111// to sa_sigaction signal handler. It may help the unwinder to get a
112// better stack trace under certain conditions. The "uc" may safely be NULL.
113extern PERFTOOLS_DLL_DECL int GetStackTraceWithContext(void** result, int max_depth,
114                                    int skip_count, const void *uc);
115
116#endif /* GOOGLE_STACKTRACE_H_ */
117