Using setjmp and longjmp
When setjmp and longjmp are used together, they provide a way to execute a non-local goto
. They are typically used in C code to pass execution control to error-handling or recovery code in a previously called routine without using the standard calling or return conventions.
Caution
Because setjmp
and longjmp
don't support correct destruction of stack frame objects portably between C++ compilers, and because they might degrade performance by preventing optimization on local variables, we don't recommend their use in C++ programs. We recommend you use try
and catch
constructs instead.
If you decide to use setjmp
and longjmp
in a C++ program, also include <setjmp.h> or <setjmpex.h> to assure correct interaction between the functions and Structured Exception Handling (SEH) or C++ exception handling.
Microsoft Specific
If you use an /EH option to compile C++ code, destructors for local objects are called during the stack unwind. However, if you use /EHs or /EHsc to compile, and one of your functions that uses noexcept calls longjmp
, then the destructor unwind for that function might not occur, depending on the optimizer state.
In portable code, when a longjmp
call is executed, correct destruction of frame-based objects is explicitly not guaranteed by the standard, and may not be supported by other compilers. To let you know, at warning level 4, a call to setjmp
causes warning C4611: interaction between '_setjmp' and C++ object destruction is non-portable.
END Microsoft Specific