 They may be viewed as an advanced version of setjmp/longjmp; whereas the latter allows only a single non-local jump up the stack, codice_1 allows the creation of multiple cooperative threads of control, each with its own stack.codice_1 was specified in POSIX.1-2001 and the Single Unix Specification, version 2, but not all Unix-like operating systems provide them.POSIX.1-2004 obsoleted these functions, and in POSIX.1-2008 they were removed, with POSIX Threads indicated as a possible replacement.