4.3BSD-Reno/share/man/cat2/sigreturn.0

SIGRETURN(2)		      1990		     SIGRETURN(2)



NNAAMMEE
     sigreturn - return from signal

SSYYNNOOPPSSIISS
     ##iinncclluuddee <<ssiiggnnaall..hh>>

     ssttrruucctt    ssiiggccoonntteexxtt {{
	  iinntt  sscc__oonnssttaacckk;;
	  iinntt  sscc__mmaasskk;;
	  iinntt  sscc__sspp;;
	  iinntt  sscc__ffpp;;
	  iinntt  sscc__aapp;;
	  iinntt  sscc__ppcc;;
	  iinntt  sscc__ppss;;
     }};;

     ssiiggrreettuurrnn((ssccpp));;
     ssttrruucctt ssiiggccoonntteexxtt **ssccpp;;

DDEESSCCRRIIPPTTIIOONN
     _S_i_g_r_e_t_u_r_n allows users to atomically unmask, switch stacks,
     and return from a signal context.	The processes signal mask
     and stack status are restored from the context.  The system
     call does not return; the users stack pointer, frame
     pointer, argument pointer, and processor status longword are
     restored from the context.  Execution resumes at the speci-
     fied pc.  This system call is used by the trampoline code,
     and _l_o_n_g_j_m_p(3) when returning from a signal to the previ-
     ously executing program.

NNOOTTEESS
     This system call is not available in 4.2BSD, hence it should
     not be used if backward compatibility is needed.

RREETTUURRNN VVAALLUUEE
     If successful, the system call does not return.  Otherwise,
     a value of -1 is returned and _e_r_r_n_o is set to indicate the
     error.

EERRRROORRSS
     _S_i_g_r_e_t_u_r_n will fail and the process context will remain
     unchanged if one of the following occurs.

     [EFAULT]	    _S_c_p points to memory that is not a valid part
		    of the process address space.

     [EINVAL]	    The process status longword is invalid or
		    would improperly raise the privilege level of
		    the process.

SSEEEE AALLSSOO
     sigvec(2), setjmp(3)



Printed 7/27/90               June				1