return from signal
() 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 specified pc.
This system call is used by the trampoline code and
returning from a signal to the previously executing program.
Note that sigcontext contains machine dependent information.
This system call is not available in 4.2BSD
should not be used if backward compatibility is needed.
If successful, the system call does not return. Otherwise, a value of -1 is
returned and errno
is set to indicate the
() will fail and the process context will
remain unchanged if one of the following occurs.
- scp points to memory that
is not a valid part of the process address space.
- The process status longword is invalid or would improperly
raise the privilege level of the process.
() function call appeared in