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setcontext(2) [sunos man page]

getcontext(2)							   System Calls 						     getcontext(2)

NAME
getcontext, setcontext - get and set current user context SYNOPSIS
#include <ucontext.h> int getcontext(ucontext_t *ucp); int setcontext(const ucontext_t *ucp); DESCRIPTION
The getcontext() function initializes the structure pointed to by ucp to the current user context of the calling process. The ucontext_t type that ucp points to defines the user context and includes the contents of the calling process' machine registers, the signal mask, and the current execution stack. The setcontext() function restores the user context pointed to by ucp. A successful call to setcontext() does not return; program execu- tion resumes at the point specified by the ucp argument passed to setcontext(). The ucp argument should be created either by a prior call to getcontext(), or by being passed as an argument to a signal handler. If the ucp argument was created with getcontext(), program execu- tion continues as if the corresponding call of getcontext() had just returned. If the ucp argument was created with makecontext(3C), pro- gram execution continues with the function passed to makecontext(3C). When that function returns, the process continues as if after a call to setcontext() with the ucp argument that was input to makecontext(3C). If the ucp argument was passed to a signal handler, program execu- tion continues with the program instruction following the instruction interrupted by the signal. If the uc_link member of the ucontext_t structure pointed to by the ucp argument is equal to 0, then this context is the main context, and the process will exit when this context returns. The effects of passing a ucp argument obtained from any other source are unspecified. RETURN VALUES
On successful completion, setcontext() does not return and getcontext() returns 0. Otherwise, -1 is returned. ERRORS
No errors are defined. USAGE
When a signal handler is executed, the current user context is saved and a new context is created. If the thread leaves the signal handler via longjmp(3UCB), then it is unspecified whether the context at the time of the corresponding setjmp(3UCB) call is restored and thus whether future calls to getcontext() will provide an accurate representation of the current context, since the context restored by longjmp(3UCB) may not contain all the information that setcontext() requires. Signal handlers should use siglongjmp(3C) instead. Portable applications should not modify or access the uc_mcontext member of ucontext_t. A portable application cannot assume that context includes any process-wide static data, possibly including errno. Users manipulating contexts should take care to handle these explicitly when required. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ SEE ALSO
sigaction(2), sigaltstack(2), sigprocmask(2), bsd_signal(3C), makecontext(3C), setjmp(3UCB), sigsetjmp(3C), ucontext.h(3HEAD), attributes(5), standards(5) SunOS 5.10 5 Feb 2001 getcontext(2)

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getcontext(2)							System Calls Manual						     getcontext(2)

NAME
getcontext(), setcontext() - get and set current user context SYNOPSIS
Deprecated Deprecated DESCRIPTION
The function initializes the structure pointed to by ucp to the current user context of the calling process. The ucontext_t type that ucp points to defines the user context and includes the contents of the calling process' machine registers, the signal mask, and the current execution stack. The function restores the user context pointed to by ucp. A successful call to does not return; program execution resumes at the point specified by the ucp argument passed to The ucp argument should be created either by a prior call to or by being passed as an argument to a signal handler. If the ucp argument was created with program execution continues as if the corresponding call of had just returned. If the ucp argument was created with program execution continues with the function passed to When that function returns, the process continues as if after a call to with the ucp argument that was input to If the ucp argument was passed to a signal handler, program execution continues with the program instruction following the instruction interrupted by the signal. If the uc_link member of the structure pointed to by the ucp argument is equal to 0, then this context is the main context, and the process will exit when this context returns. The effects of passing a ucp argument obtained from any other source are unspecified. RETURN VALUE
On successful completion, does not return and returns 0. Otherwise, a value of -1 is returned. WARNINGS
and are deprecated and should be used only by legacy applications. Context APIs are not recommended due to possible compatibility problems from release to release, because context APIs are very architec- ture-specific. The context APIs "expose" the architecture to the application, such that the application may not be compatible with all releases. If you must use context APIs, be aware of the following: o Do not copy the context yourself. It is not contiguous. The context may have pointers that may point back to the original context rather than in the copied context; hence, it will be broken. o The size of the context will vary in length from release to release. ERRORS
No errors are defined. APPLICATION USAGE
When a signal handler is executed, the current user context is saved and a new context is created. If the process leaves the signal handler via then it is unspecified whether the context at the time of the corresponding call is restored and thus whether future calls to will pro- vide an accurate representation of the current context, since the context restored by may not contain all the information that requires. Signal handlers should use or instead. Portable applications should not modify or access the uc_mcontext member of ucontext_t. A portable application cannot assume that context includes any process-wide static data, possibly including Users manipulating contexts should take care to handle these explicitly when required. SEE ALSO
makecontext(2), sigaction(2), sigaltstack(2), sigprocmask(2), setjmp(3C), sigsetjmp(3C), <ucontext.h>. Deprecated getcontext(2)

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