1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
|
\documentclass{article}
\usepackage[fancyhdr,pdf]{latex2man}
\input{common.tex}
\begin{document}
\begin{Name}{3libunwind}{unw\_init\_local}{David Mosberger-Tang}{Programming Library}{unw\_init\_local}unw\_init\_local -- initialize cursor for local unwinding
\end{Name}
\section{Synopsis}
\File{\#include $<$libunwind.h$>$}\\
\Type{int} \Func{unw\_init\_local}(\Type{unw\_cursor\_t~*}\Var{c}, \Type{unw\_context\_t~*}\Var{ctxt});\\
\Type{int} \Func{unw\_init\_local2}(\Type{unw\_cursor\_t~*}\Var{c}, \Type{unw\_context\_t~*}\Var{ctxt}, \Type{int} \Var{flag});\\
\section{Description}
The \Func{unw\_init\_local}() routine initializes the unwind cursor
pointed to by \Var{c} with the machine state in the context structure
pointed to by \Var{ctxt}. As such, the machine state pointed to by
\Var{ctxt} identifies the initial stack frame at which unwinding
starts. The machine state is expected to be one provided by a call to
\Func{unw\_getcontext}(); as such, the instruction pointer may point to
the instruction after the last instruction of a function, and
\Prog{libunwind} will back-up the instruction pointer before beginning
a walk up the call stack. The machine state must remain valid for the
duration for which the cursor \Var{c} is in use.
The \Func{unw\_init\_local}() routine can be used only for unwinding in
the address space of the current process (i.e., for local unwinding).
For all other cases, \Func{unw\_init\_remote}() must be used instead.
However, unwind performance may be better when using
\Func{unw\_init\_local}(). Also, \Func{unw\_init\_local}() is
available even when \Const{UNW\_LOCAL\_ONLY} has been defined before
including \File{$<$libunwind.h$>$}, whereas \Func{unw\_init\_remote}()
is not.
If the \Type{unw\_context\_t} is known to be a signal frame (i.e.,
from the third argument in a sigaction handler on linux),
\Func{unw\_init\_local2}() should be used for correct initialization
on some platforms, passing the \Const{UNW\_INIT\_SIGNAL\_FRAME} flag.
\section{Return Value}
On successful completion, \Func{unw\_init\_local}() returns 0.
Otherwise the negative value of one of the error codes below is
returned.
\section{Thread and Signal Safety}
\Func{unw\_init\_local}() is thread safe as well as safe to use from a
signal handler.
\section{Errors}
\begin{Description}
\item[\Const{UNW\_EINVAL}] \Func{unw\_init\_local}() was called in a
version of \Prog{libunwind} which supports remote unwinding only
(this normally happens when calling \Func{unw\_init\_local}() for a
cross-platform version of \Prog{libunwind}).
\item[\Const{UNW\_EUNSPEC}] An unspecified error occurred.
\item[\Const{UNW\_EBADREG}] A register needed by \Func{unw\_init\_local}()
wasn't accessible.
\end{Description}
\section{See Also}
\SeeAlso{libunwind}(3libunwind),
\SeeAlso{unw\_init\_remote}(3libunwind)
\section{Author}
\noindent
David Mosberger-Tang\\
Email: \Email{dmosberger@gmail.com}\\
WWW: \URL{http://www.nongnu.org/libunwind/}.
\LatexManEnd
\end{document}
|
