Top Forums Programming why multiple SIGINT raises when i hit C-c Post 302356768 by fpmurphy on Sunday 27th of September 2009 01:29:28 PM
Old 09-27-2009
Humm, the generally accepted way to handle a signal such as Ctrl-C in a threaded application is to create a specific signal handling thread which waits for a Ctrl-C and then sets a mutex or condition variable which the other threads check on a regular basis.

See Section 6.6 of Programming with POSIX Threads by Dave Butenhof. He provides example code for exactly what you are looking to do on starting on page 228. You can also find other examples if you do a web search.

By the way, it is bad practice to use setjmp and longjmp in threaded applications. Some versions of threads libraries actually use setjmp/longjmp internally for various purposes.

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LONGJMP(3)						     Linux Programmer's Manual							LONGJMP(3)

longjmp, siglongjmp - nonlocal jump to a saved stack context SYNOPSIS
#include <setjmp.h> void longjmp(jmp_buf env, int val); void siglongjmp(sigjmp_buf env, int val); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): siglongjmp(): _POSIX_C_SOURCE >= 1 || _XOPEN_SOURCE || _POSIX_C_SOURCE DESCRIPTION
longjmp() and setjmp(3) are useful for dealing with errors and interrupts encountered in a low-level subroutine of a program. longjmp() restores the environment saved by the last call of setjmp(3) with the corresponding env argument. After longjmp() is completed, program execution continues as if the corresponding call of setjmp(3) had just returned the value val. longjmp() cannot cause 0 to be returned. If longjmp() is invoked with a second argument of 0, 1 will be returned instead. siglongjmp() is similar to longjmp() except for the type of its env argument. If, and only if, the sigsetjmp(3) call that set this env used a nonzero savesigs flag, siglongjmp() also restores the signal mask that was saved by sigsetjmp(3). RETURN VALUE
These functions never return. CONFORMING TO
C89, C99, and POSIX.1-2001 specify longjmp(). POSIX.1-2001 specifies siglongjmp(). NOTES
POSIX does not specify whether longjmp() will restore the signal context (see setjmp(3) for some more details). If you want to portably save and restore signal masks, use sigsetjmp(3) and siglongjmp(). The values of automatic variables are unspecified after a call to longjmp() if they meet all the following criteria: o they are local to the function that made the corresponding setjmp(3) call; o their values are changed between the calls to setjmp(3) and longjmp(); and o they are not declared as volatile. Analogous remarks apply for siglongjmp(). longjmp() and siglongjmp() make programs hard to understand and maintain. If possible an alternative should be used. SEE ALSO
setjmp(3), sigsetjmp(3) COLOPHON
This page is part of release 3.53 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at 2009-01-13 LONGJMP(3)

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