Unix/Linux Go Back    

RedHat 9 (Linux i386) - man page for swapcontext (redhat section 3)

Linux & Unix Commands - Search Man Pages
Man Page or Keyword Search:   man
Select Man Page Set:       apropos Keyword Search (sections above)

MAKECONTEXT(3)			    Linux Programmer's Manual			   MAKECONTEXT(3)

       makecontext, swapcontext - manipulate user context

       #include <ucontext.h>

       void makecontext(ucontext_t *ucp, void *func(), int argc, ...);
       int swapcontext (ucontext_t *oucp, ucontext_t *ucp);

       In  a  SysV-like  environment, one has the type ucontext_t defined in <ucontext.h> and the
       four functions getcontext(), setcontext(),  makecontext()  and  swapcontext()  that  allow
       user-level context switching between multiple threads of control within a process.

       For the type and the first two functions, see getcontext(2).

       The makecontext() function modifies the context pointed to by ucp (which was obtained from
       a call to getcontext()).  Before calling makecontext(), one should allocate  a  new  stack
       for this context, assigning to ucp->uc_stack, and define a successor context, assigning to
       ucp->uc_link.  When this context is later activated (using setcontext() or  swapcontext())
       then first the function func is called, with the arguments specified following argc (where
       argc must contain the number of these arguments), and when this function returns, the suc-
       cessor context is activated. When the successor context pointer is NULL, the thread exits.

       The  swapcontext() function saves the current context in the structure pointed to by oucp,
       and then activates the context pointed to by ucp.

       When successful, makecontext() returns 0 and swapcontext() does not return.  (But  we  may
       return later, in case oucp is activated, in which case it looks like swapcontext() returns
       0.)  On error, both return -1 and set errno appropriately.

       ENOMEM Insufficient stack space left.

       The interpretation of ucp->uc_stack is just as in sigaltstack(2), namely, this struct con-
       tains  start  and length of a memory area to be used as stack, regardless of the direction
       of growth of the stack. So, it is not necessary for the user program to worry  about  this

       SUSv2, POSIX 1003.1-2001.

       getcontext(2), sigaction(2), sigaltstack(2), sigprocmask(2), sigsetjmp(3)

Linux 2.4				    2001-11-15				   MAKECONTEXT(3)
Unix & Linux Commands & Man Pages : ©2000 - 2018 Unix and Linux Forums

All times are GMT -4. The time now is 06:58 AM.