setjmp

I have written a segmentation fault handler, using sigsetjmp and siglongjmp. Once it goes to the signal handler, i invoke siglongjmp so that the faulty instruction is skipped. Problem is, i again want to cause SIGSEGV and go to the same handler, but now sigsetjmp will return 1. How to reset sigsetjmp? Here is my code: #include <stdio.h> #include <memory.h> #include <stdlib.h> #include <unistd.h> #include <sys/mman.h> #include <sys/types.h> #include <fcntl.h> #include <signal.h> #include <setjmp.h> sigjmp_buf env, env1; void SIGSEGV_handler(int signal) { printf("Segmentation fault caught\n");

I was investigating setjmp/longjmp and found out that setjmp saves registers such as instruction pointer, stack pointer etc... However what I don't get here is that, can't the data in the stack of the thread itself be modified between the call to setjmp and longjmp . In that case, wouldn't longjmp not work as expected. To make it clear, for example, when longjmp restores the stack pointer, say the data in the memory the stack pointer is pointing now is not the same as was when setjmp was called. Can this happen? And if that happens, aren't we in trouble? Also what is meant by the statement, "

Hi I'd like to read good tutorials on setjmp/longjmp in C. It'd be better if there're examples which are real rather than artificial. Thanks. It's not really a tutorial as such, but the libpng documentation describes how the library uses setjmp/longjmp to do error handling. Eli Bendersky The book "C interfaces and implementation" explains the concept well and implements a usable "exception" simulation in C using these constructs. The code for it (chapter 4) is freely available online here . Edit: also see this SO thread Then you should read Advanced Programming in the UNIX(R) Environment (2nd

I have to use C for one project and I am thinking of using longjmp/setjmp for error handling as I think it will be much easier to handle error in one central place than return codes. I would appreciate if there are some leads on how to do this. I am particularly concerned with resource cleanup being correctly done if any such error occurs. Also how do I handle errors that result in multi-threaded programs using them? Even better, is there some C library that already exists for error/exception handling? Have a look at this example/tutorial: http://www.di.unipi.it/~nids/docs/longjump_try_trow

After invoking longjmp(), non-volatile-qualified local objects should not be accessed if their values could have changed since the invocation of setjmp(). Their value in this case is considered indeterminate, and accessing them is undefined behavior. Now my question is why volatile works in this situation? Wouldn't change in that volatile variable still fail the longjmp? For example, how longjmp will work correctly in the example given below? When the code get backs to setjmp after longjmp, wouldn't the value of local_var be 2 instead of 1? void some_function() { volatile int local_var = 1;