src/gperftools/stacktrace.h

// -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*-
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// ---
// Author: Sanjay Ghemawat
//
// Routines to extract the current stack trace.  These functions are
// thread-safe.

#ifndef GOOGLE_STACKTRACE_H_
#define GOOGLE_STACKTRACE_H_

// Annoying stuff for windows -- makes sure clients can import these functions
#ifndef PERFTOOLS_DLL_DECL
# ifdef _WIN32
#   define PERFTOOLS_DLL_DECL  __declspec(dllimport)
# else
#   define PERFTOOLS_DLL_DECL
# endif
#endif


// Skips the most recent "skip_count" stack frames (also skips the
// frame generated for the "GetStackFrames" routine itself), and then
// records the pc values for up to the next "max_depth" frames in
// "result", and the corresponding stack frame sizes in "sizes".
// Returns the number of values recorded in "result"/"sizes".
//
// Example:
//      main() { foo(); }
//      foo() { bar(); }
//      bar() {
//        void* result[10];
//        int sizes[10];
//        int depth = GetStackFrames(result, sizes, 10, 1);
//      }
//
// The GetStackFrames call will skip the frame for "bar".  It will
// return 2 and will produce pc values that map to the following
// procedures:
//      result[0]       foo
//      result[1]       main
// (Actually, there may be a few more entries after "main" to account for
// startup procedures.)
// And corresponding stack frame sizes will also be recorded:
//    sizes[0]       16
//    sizes[1]       16
// (Stack frame sizes of 16 above are just for illustration purposes.)
// Stack frame sizes of 0 or less indicate that those frame sizes couldn't
// be identified.
//
// This routine may return fewer stack frame entries than are
// available. Also note that "result" and "sizes" must both be non-NULL.
extern PERFTOOLS_DLL_DECL int GetStackFrames(void** result, int* sizes, int max_depth,
                          int skip_count);

// Same as above, but to be used from a signal handler. The "uc" parameter
// should be the pointer to ucontext_t which was passed as the 3rd parameter
// to sa_sigaction signal handler. It may help the unwinder to get a
// better stack trace under certain conditions. The "uc" may safely be NULL.
extern PERFTOOLS_DLL_DECL int GetStackFramesWithContext(void** result, int* sizes, int max_depth,
                                     int skip_count, const void *uc);

// This is similar to the GetStackFrames routine, except that it returns
// the stack trace only, and not the stack frame sizes as well.
// Example:
//      main() { foo(); }
//      foo() { bar(); }
//      bar() {
//        void* result[10];
//        int depth = GetStackTrace(result, 10, 1);
//      }
//
// This produces:
//      result[0]       foo
//      result[1]       main
//           ....       ...
//
// "result" must not be NULL.
extern PERFTOOLS_DLL_DECL int GetStackTrace(void** result, int max_depth,
                                            int skip_count);

// Same as above, but to be used from a signal handler. The "uc" parameter
// should be the pointer to ucontext_t which was passed as the 3rd parameter
// to sa_sigaction signal handler. It may help the unwinder to get a
// better stack trace under certain conditions. The "uc" may safely be NULL.
extern PERFTOOLS_DLL_DECL int GetStackTraceWithContext(void** result, int max_depth,
                                    int skip_count, const void *uc);

#endif /* GOOGLE_STACKTRACE_H_ */