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Async signal safe backend implmented and notes about async-safety were added to the docs.
1 parent 7cbe206 commit fd51339

14 files changed

Lines changed: 182 additions & 35 deletions

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‎build/Jamfile.v2‎

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@@ -12,6 +12,7 @@ project
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;
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lib dl : : <link>shared ;
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lib gcc_s : : <link>shared ;
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lib Dbghelp ;
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actions mp_simple_run_action
@@ -31,6 +32,9 @@ rule mp-run-simple ( sources + : args * : input-files * : requirements * : targe
3132
mp-run-simple has_backtrace.cpp : : : : backtrace ;
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explicit backtrace ;
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mp-run-simple has_unwind.cpp : : : : unwind ;
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explicit unwind ;
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mp-run-simple has_windbg.cpp : : : : WinDbg ;
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explicit WinDbg ;
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@@ -62,6 +66,21 @@ lib boost_stacktrace_backtrace
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boost-install boost_stacktrace_backtrace ;
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lib boost_stacktrace_unwind
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: # sources
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../src/unwind.cpp
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: # requirements
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<warnings>all
74+
<target-os>linux:<library>dl
75+
<link>shared:<define>BOOST_STACKTRACE_DYN_LINK=1
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[ check-target-builds ../build//unwind : : <build>no ]
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: # default build
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: # usage-requirements
79+
#<link>shared:<define>BOOST_STACKTRACE_DYN_LINK=1
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;
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82+
boost-install boost_stacktrace_unwind ;
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lib boost_stacktrace_windbg
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: # sources
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../src/windbg.cpp

‎build/has_backtrace.cpp‎

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@@ -1,3 +1,8 @@
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// Copyright Antony Polukhin, 2016.
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//
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// Distributed under the Boost Software License, Version 1.0. (See
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// accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#include <dlfcn.h>
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#include <execinfo.h>

‎build/has_unwind.cpp‎

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@@ -0,0 +1,11 @@
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// Copyright Antony Polukhin, 2016.
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//
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// Distributed under the Boost Software License, Version 1.0. (See
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// accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#include <unwind.h>
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int main() {
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}

‎doc/stacktrace.qbk‎

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@@ -247,11 +247,11 @@ By default Boost.Stacktrace is a header-only library and it attempts to detect t
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You can define the following macros to explicitly specify backend that you're willing to use in header-only mode (those macros have no effect if defined *BOOST_STACKTRACE_LINK* or *BOOST_STACKTRACE_DYN_LINK*):
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[table:configbackend Header only backend specifications
250-
[[Macro name] [Effect] [Platforms] [Uses debug information [footnote This will provide more readable backtraces if the binary is built with debug information.]] [Uses dynamic exports information [footnote This will provide readable function names in backtrace for functions that are exported by the binary.]] [Construction speed] [Async signal safe[footnote Absolutely safe to use that backend in async signal handler.]]]
251-
[[*BOOST_STACKTRACE_USE_LIBUNWIND*] [Use libunwind tracing backend. This is the best known backend for POSIX systems that requires linking with libunwind library.] [POSIX] [yes] [yes] [slow] [no]]
252-
[[*BOOST_STACKTRACE_USE_WINDBG*] [Use Windows specific tracing backend that uses DbgHelp. This is the best and only known backend for Windows platform that requires linking with DbgHelp library.] [Windows] [yes] [yes] [fast] [no]]
253-
[[*BOOST_STACKTRACE_USE_BACKTRACE*] [Use tracing backend that calls POSIX function backtrace. This is a fallback backend for POSIX platforms that requires linking with libdl library.] [POSIX] [no] [yes] [fast] [no]]
254-
[[*BOOST_STACKTRACE_USE_NOOP*] [Use noop tracing backend that does nothing. Use this backend if you wish to disable backtracing, `stacktrace::size()` with that backend always return 0. ] [POSIX and Windows] [no] [no] [noop] [yes]]
250+
[[Macro name] [Effect] [Platforms] [Uses debug information [footnote This will provide more readable backtraces if the binary is built with debug information.]] [Uses dynamic exports information [footnote This will provide readable function names in backtrace for functions that are exported by the binary.]] [Async signal safe[footnote Absolutely safe to construct instances of [classref boost::stacktrace::stacktrace] in async signal handlers using that backend.]]]
251+
[[*BOOST_STACKTRACE_USE_UNWIND*] [Use unwind tracing backend. This is the best known backend for POSIX systems that requires LSB Core Specification 4.1 from OS. Requires linking with libdl library.] [POSIX] [yes] [yes] [Constructors]]
252+
[[*BOOST_STACKTRACE_USE_WINDBG*] [Use Windows specific tracing backend that uses DbgHelp. This is the best and only known backend for Windows platform that requires linking with DbgHelp library.] [Windows] [yes] [yes] [???]]
253+
[[*BOOST_STACKTRACE_USE_BACKTRACE*] [Use tracing backend that calls POSIX function `backtrace`. Requires linking with libdl library.] [POSIX] [no] [yes] [no]]
254+
[[*BOOST_STACKTRACE_USE_NOOP*] [Use noop tracing backend that does nothing. Use this backend if you wish to disable backtracing, `stacktrace::size()` with that backend always return 0. ] [POSIX and Windows] [no] [no] [all functions]]
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]
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257257

@@ -264,7 +264,7 @@ You may use the following macros to improve build times or to be able to switch
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265265
If one of the link macros is defined, you have to manually link your binary with one of the libraries that has the backend implementation:
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267-
* boost_stacktrace_libunwind
267+
* boost_stacktrace_unwind
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* boost_stacktrace_windbg
269269
* boost_stacktrace_backtrace
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* boost_stacktrace_noop

‎example/getting_started.cpp‎

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@@ -99,7 +99,7 @@ void my_terminate_handler() {
9999
void my_signal_handler(int signum) {
100100
boost::stacktrace::stacktrace bt;
101101
if (bt) {
102-
std::cerr << "Signal " << signum << ", backtrace:\n" << boost::stacktrace::stacktrace() << '\n'; // ``[footnote Strictly speaking this code is not async-signal-safe, but we have SIGSEGV already it could hardly become worse. [link boost_stacktrace.build_macros_and_backends Section "Build, Macros and Backends"] describes async-signal-safe backends, so if you will use the noop backend code becomes absolutely valid as that backens always returns 0 frames and `operator<<` will be never called. ]``
102+
std::cerr << "Signal " << signum << ", backtrace:\n" << boost::stacktrace::stacktrace() << '\n'; // ``[footnote Strictly speaking this code is not async-signal-safe, because it uses std::cerr. [link boost_stacktrace.build_macros_and_backends Section "Build, Macros and Backends"] describes async-signal-safe backends, so if you will use the noop backend code becomes absolutely valid as that backens always returns 0 frames and `operator<<` will be never called. ]``
103103
}
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std::abort();
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}

‎include/boost/stacktrace/const_iterator.hpp‎

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Original file line numberDiff line numberDiff line change
@@ -20,17 +20,22 @@
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namespace boost { namespace stacktrace {
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#ifdef BOOST_STACKTRACE_DOXYGEN_INVOKED
25+
/// Random access iterator over frames that returns boost::stacktrace::frame on dereference
26+
class const_iterator: implementation_details {};
27+
28+
#else
29+
2330
// Forward declarations
2431
class stacktrace;
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26-
/// Random access iterator over frames that returns `frame` on dereference.
2733
class const_iterator: public boost::iterator_facade<
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const_iterator,
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frame,
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boost::random_access_traversal_tag,
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frame>
3238
{
33-
/// @cond
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typedef boost::iterator_facade<
3540
const_iterator,
3641
frame,
@@ -73,9 +78,10 @@ class const_iterator: public boost::iterator_facade<
7378
BOOST_ASSERT(impl_ == it.impl_);
7479
return it.frame_no_ - frame_no_;
7580
}
76-
/// @endcond
7781
};
7882

83+
#endif // #ifdef BOOST_STACKTRACE_DOXYGEN_INVOKED
84+
7985
}} // namespace boost::stacktrace
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8187
#endif // BOOST_STACKTRACE_CONST_ITERATOR_HPP

‎include/boost/stacktrace/detail/backend.hpp‎

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@@ -25,20 +25,21 @@
2525
#endif
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2727
// Backend autodetection
28-
#if !defined(BOOST_STACKTRACE_USE_NOOP) && !defined(BOOST_STACKTRACE_USE_WINDBG) && !defined(BOOST_STACKTRACE_USE_LIBUNWIND) \
29-
&& !defined(BOOST_STACKTRACE_USE_BACKTRACE) &&!defined(BOOST_STACKTRACE_USE_HEADER)
28+
#if !defined(BOOST_STACKTRACE_USE_NOOP) && !defined(BOOST_STACKTRACE_USE_WINDBG) && !defined(BOOST_STACKTRACE_USE_UNWIND) \
29+
&& !defined(BOOST_STACKTRACE_USE_BACKTRACE) && !defined(BOOST_STACKTRACE_USE_HEADER)
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3131
#if defined(__has_include) && (!defined(__GNUC__) || __GNUC__ > 4 || BOOST_CLANG)
32-
# if __has_include(<execinfo.h>)
33-
# define BOOST_STACKTRACE_USE_BACKTRACE
34-
# elif __has_include("Dbgeng.h")
32+
# if __has_include("Dbgeng.h")
3533
# define BOOST_STACKTRACE_USE_WINDBG
34+
# else
35+
# define BOOST_STACKTRACE_USE_UNWIND
3636
# endif
3737
#else
3838
# if defined(BOOST_WINDOWS)
3939
# define BOOST_STACKTRACE_USE_WINDBG
4040
# else
41-
# define BOOST_STACKTRACE_USE_BACKTRACE
41+
# define BOOST_STACKTRACE_USE_UNWIND
42+
//# define BOOST_STACKTRACE_USE_BACKTRACE
4243
# endif
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#endif
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‎include/boost/stacktrace/detail/backend.ipp‎

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@@ -18,7 +18,7 @@
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# include <boost/stacktrace/detail/backend_noop.hpp>
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#elif defined(BOOST_STACKTRACE_USE_WINDBG)
2020
# include <boost/stacktrace/detail/backend_windows.hpp>
21-
#elif defined(BOOST_STACKTRACE_USE_BACKTRACE)
21+
#elif defined(BOOST_STACKTRACE_USE_BACKTRACE) || defined(BOOST_STACKTRACE_USE_UNWIND)
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# include <boost/stacktrace/detail/backend_linux.hpp>
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#else
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# error No suitable backtrace backend found

‎include/boost/stacktrace/detail/backend_linux.hpp‎

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@@ -18,6 +18,10 @@
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#include <boost/lexical_cast/try_lexical_convert.hpp>
1919
#include <algorithm>
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21+
#if defined(BOOST_STACKTRACE_USE_UNWIND)
22+
#include <unwind.h>
23+
#endif
24+
2125
#include <dlfcn.h>
2226
#include <execinfo.h>
2327
#include <cstdio>
@@ -163,18 +167,51 @@ static inline std::string try_demangle(const char* mangled) {
163167
return res;
164168
}
165169

170+
171+
172+
173+
#if defined(BOOST_STACKTRACE_USE_UNWIND)
174+
struct unwind_state {
175+
void** current;
176+
void** end;
177+
};
178+
179+
inline _Unwind_Reason_Code unwind_callback(struct _Unwind_Context* context, void* arg) {
180+
unwind_state* state = static_cast<unwind_state*>(arg);
181+
*state->current = reinterpret_cast<void*>(
182+
_Unwind_GetIP(context)
183+
);
184+
185+
++state->current;
186+
if (!*(state->current - 1) || state->current == state->end) {
187+
return _URC_END_OF_STACK;
188+
}
189+
return _URC_NO_REASON;
190+
}
191+
#endif
192+
193+
194+
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166196
backend::backend(void* memory, std::size_t size, std::size_t& hash_code) BOOST_NOEXCEPT
167197
: data_(static_cast<backtrace_holder*>(memory))
168198
{
169199
new (data_) backtrace_holder();
170200
data_->frames_count = 0;
171201
hash_code = 0;
172202

173-
// TODO: Not async signal safe. Use _Unwind_Backtrace, _Unwind_GetIP
203+
#if defined(BOOST_STACKTRACE_USE_UNWIND)
204+
unwind_state state = { data_->buffer, data_->buffer + data_->frames_count };
205+
_Unwind_Backtrace(&unwind_callback, &state);
206+
data_->frames_count = state.current - data_->buffer;
207+
#elif defined(BOOST_STACKTRACE_USE_BACKTRACE)
174208
data_->frames_count = ::backtrace(data_->buffer, (size - sizeof(backtrace_holder)) / sizeof(void*));
175209
if (data_->buffer[data_->frames_count - 1] == 0) {
176210
-- data_->frames_count;
177211
}
212+
#else
213+
# error No stacktrace backend defined. Define BOOST_STACKTRACE_USE_UNWIND or BOOST_STACKTRACE_USE_BACKTRACE
214+
#endif
178215

179216
hash_code = boost::hash_range(data_->buffer, data_->buffer + data_->frames_count);
180217
}

‎include/boost/stacktrace/frame.hpp‎

Lines changed: 20 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -35,33 +35,43 @@ class frame {
3535
frame() = delete;
3636

3737
/// @brief Copy constructs frame.
38-
/// @throws Nothing.
3938
///
4039
/// @b Complexity: O(1).
40+
///
41+
/// @b Async-Handler-Safety: Safe.
42+
/// @throws Nothing.
4143
frame(const frame&) = default;
4244

4345
/// @brief Copy assigns frame.
44-
/// @throws Nothing.
4546
///
4647
/// @b Complexity: O(1).
48+
///
49+
/// @b Async-Handler-Safety: Safe.
50+
/// @throws Nothing.
4751
frame& operator=(const frame&) = default;
4852
#endif
4953

5054
/// @brief Constructs frame that can extract information from addr at runtime.
51-
/// @throws Nothing.
5255
///
5356
/// @b Complexity: O(1).
57+
///
58+
/// @b Async-Handler-Safety: Safe.
59+
/// @throws Nothing.
5460
explicit frame(const void* addr) BOOST_NOEXCEPT
5561
: addr_(addr)
5662
{}
5763

5864
/// @returns Name of the frame (function name in a human readable form).
65+
///
66+
/// @b Async-Handler-Safety: Unsafe.
5967
/// @throws std::bad_alloc if not enough memory to construct resulting string.
6068
std::string name() const {
6169
return boost::stacktrace::detail::backend::get_name(address());
6270
}
6371

6472
/// @returns Address of the frame function.
73+
///
74+
/// @b Async-Handler-Safety: Safe.
6575
/// @throws Nothing.
6676
const void* address() const BOOST_NOEXCEPT {
6777
return addr_;
@@ -70,31 +80,35 @@ class frame {
7080
/// @returns Path to the source file, were the function of the frame is defined. Returns empty string
7181
/// if this->source_line() == 0.
7282
/// @throws std::bad_alloc if not enough memory to construct resulting string.
83+
///
84+
/// @b Async-Handler-Safety: Unsafe.
7385
std::string source_file() const {
7486
return boost::stacktrace::detail::backend::get_source_file(address());
7587
}
7688

7789
/// @returns Code line in the source file, were the function of the frame is defined.
7890
/// @throws std::bad_alloc if not enough memory to construct string for internal needs.
91+
///
92+
/// @b Async-Handler-Safety: Unsafe.
7993
std::size_t source_line() const {
8094
return boost::stacktrace::detail::backend::get_source_line(address());
8195
}
8296
};
8397

84-
/// Comparison operators that provide platform dependant ordering and have O(1) complexity.
98+
/// Comparison operators that provide platform dependant ordering and have O(1) complexity; are Async-Handler-Safe.
8599
inline bool operator< (const frame& lhs, const frame& rhs) BOOST_NOEXCEPT { return lhs.address() < rhs.address(); }
86100
inline bool operator> (const frame& lhs, const frame& rhs) BOOST_NOEXCEPT { return rhs < lhs; }
87101
inline bool operator<=(const frame& lhs, const frame& rhs) BOOST_NOEXCEPT { return !(lhs > rhs); }
88102
inline bool operator>=(const frame& lhs, const frame& rhs) BOOST_NOEXCEPT { return !(lhs < rhs); }
89103
inline bool operator==(const frame& lhs, const frame& rhs) BOOST_NOEXCEPT { return lhs.address() == rhs.address(); }
90104
inline bool operator!=(const frame& lhs, const frame& rhs) BOOST_NOEXCEPT { return !(lhs == rhs); }
91105

92-
/// Hashing support, O(1) complexity.
106+
/// Hashing support, O(1) complexity; Async-Handler-Safe.
93107
inline std::size_t hash_value(const frame& f) BOOST_NOEXCEPT {
94108
return reinterpret_cast<std::size_t>(f.address());
95109
}
96110

97-
/// Outputs stacktrace::frame in a human readable format to output stream.
111+
/// Outputs stacktrace::frame in a human readable format to output stream; unsafe to use in async handlers.
98112
template <class CharT, class TraitsT>
99113
std::basic_ostream<CharT, TraitsT>& operator<<(std::basic_ostream<CharT, TraitsT>& os, const frame& f) {
100114
os << f.name();

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