sigreturn(2) -- Linux man page
NAMEsigreturn - return from signal handler and cleanup stack frame
SYNOPSISint sigreturn(unsigned long __unused);
DESCRIPTIONWhen the Linux kernel creates the stack frame for a signal handler, a call to sigreturn is inserted into the stack frame so that the the signal handler will call sigreturn upon return. This inserted call to sigreturn cleans up the stack so that the process can restart from where it was interrupted by the signal.
RETURN VALUEsigreturn never returns.
WARNINGThe sigreturn call is used by the kernel to implement signal handlers. It should never be called directly. Better yet, the specific use of the __unused argument varies depending on the architecture.
CONFORMING TOsigreturn is specific to Linux and should not be used in programs intended to be portable.
SEE ALSOkill(2), signal(2), signal(7)