mirror of
https://github.com/tobast/libunwind-eh_elf.git
synced 2024-11-18 13:57:38 +01:00
89 lines
3.3 KiB
TeX
89 lines
3.3 KiB
TeX
\documentclass{article}
|
|
\usepackage[fancyhdr,pdf]{latex2man}
|
|
|
|
\input{common.tex}
|
|
|
|
\begin{document}
|
|
|
|
\begin{Name}{3}{libunwind-setjmp}{David Mosberger-Tang}{Programming Library}{libunwind-based non-local gotos}libunwind-setjmp -- libunwind-based non-local gotos
|
|
\end{Name}
|
|
|
|
\section{Synopsis}
|
|
|
|
\File{\#include $<$setjmp.h$>$}\\
|
|
|
|
\noindent
|
|
\Type{int} \Func{setjmp}(\Type{jmp\_buf}~\Var{env});\\
|
|
\Type{void} \Func{longjmp}(\Type{jmp\_buf}~\Var{env}, \Type{int}~\Var{val});\\
|
|
\Type{int} \Func{\_setjmp}(\Type{jmp\_buf}~\Var{env});\\
|
|
\Type{void} \Func{\_longjmp}(\Type{jmp\_buf}~\Var{env}, \Type{int}~\Var{val});\\
|
|
\Type{int} \Func{setjmp}(\Type{sigjmp\_buf}~\Var{env}, \Type{int}~\Var{savemask});\\
|
|
\Type{void} \Func{siglongjmp}(\Type{sigjmp\_buf}~\Var{env}, \Type{int}~\Var{val});\\
|
|
|
|
\section{Description}
|
|
|
|
The \Prog{unwind-setjmp} library offers a \Prog{libunwind}-based
|
|
implementation of non-local gotos. This implementation is intended to
|
|
be a drop-in replacement for the normal, system-provided routines of
|
|
the same name. The main advantage of using the \Prog{unwind-setjmp}
|
|
library is that setting up a non-local goto via one of the
|
|
\Func{setjmp}() routines is very fast. Typically, just 2 or 3 words
|
|
need to be saved in the jump-buffer (plus one call to
|
|
\Func{sigprocmask}(2), in the case of \Func{sigsetjmp}). On the
|
|
other hand, executing a non-local goto by calling one of the
|
|
\Func{longjmp}() routines tends to be much slower than with the
|
|
system-provided routines. In fact, the time spent on a
|
|
\Func{longjmp}() will be proportional to the number of call frames
|
|
that exist between the points where \Func{setjmp}() and
|
|
\Func{longjmp}() were called. For this reason, the
|
|
\Prog{unwind-setjmp} library is beneficial primarily in applications
|
|
that frequently call \Func{setjmp}() but only rarely call
|
|
\Func{longjmp}().
|
|
|
|
\section{Caveats}
|
|
|
|
\begin{itemize}
|
|
\item The correct operation of this library depends on the presence of
|
|
correct unwind information. On newer platforms, this is rarely an
|
|
issue. On older platforms, care needs to be taken to
|
|
ensure that each of the functions whose stack frames may have to be
|
|
unwound during a \Func{longjmp}() have correct unwind information
|
|
(on those platforms, there is usually a compiler-switch, such as
|
|
\Opt{-funwind-tables}, to request the generation of unwind
|
|
information).
|
|
\item The contents of \Type{jmp\_buf} and \Type{sigjmp\_buf} as setup
|
|
and used by these routines is completely different from the ones
|
|
used by the system-provided routines. Thus, a jump-buffer created
|
|
by the libunwind-based \Func{setjmp}()/\Func{\_setjmp} may only be
|
|
used in a call to the libunwind-based
|
|
\Func{longjmp}()/\Func{\_longjmp}(). The analogous applies for
|
|
\Type{sigjmp\_buf} with \Func{sigsetjmp}() and \Func{siglongjmp}().
|
|
\end{itemize}
|
|
|
|
\section{Files}
|
|
|
|
\begin{Description}
|
|
\item[\Opt{-l}\File{unwind-setjmp}] The library an application should
|
|
be linked against to ensure it uses the libunwind-based non-local
|
|
goto routines.
|
|
\end{Description}
|
|
|
|
|
|
\section{See Also}
|
|
|
|
\SeeAlso{libunwind(3)},
|
|
setjmp(3), longjmp(3),
|
|
\_setjmp(3), \_longjmp(3),
|
|
sigsetjmp(3), siglongjmp(3)
|
|
|
|
\section{Author}
|
|
|
|
\noindent
|
|
David Mosberger-Tang\\
|
|
Hewlett-Packard Labs\\
|
|
Palo-Alto, CA 94304\\
|
|
Email: \Email{davidm@hpl.hp.com}\\
|
|
WWW: \URL{http://www.hpl.hp.com/research/linux/libunwind/}.
|
|
\LatexManEnd
|
|
|
|
\end{document}
|