prctl - operations on a process


       #include <sys/prctl.h>

       int  prctl(int  option,  unsigned long arg2, unsigned long
       arg3 , unsigned long arg4, unsigned long arg5);


       prctl is called with a first argument describing  what  to
       do  (with  values defined in <linux/prctl.h>), and further
       parameters with a significance depending on the first one.
       The first argument can be:

              (since  Linux  2.1.57) Set the parent process death
              signal of the current process  to  arg2  (either  a
              signal  value  in  the  range  1..maxsig,  or  0 to
              clear).  This is the signal that the  current  pro­
              cess  will  get when its parent dies. This value is
              cleared upon a fork().

              (since Linux 2.3.15) Read the current value of  the
              parent  process death signal into the (int *) arg2.


       On success, zero is returned.  On error, -1  is  returned,
       and errno is set appropriately.


       EINVAL The  value  of  option  is not recognized, or it is
              PR_SET_PDEATHSIG and arg2 is not zero or  a  signal


       This call is Linux-specific.  IRIX has a prctl system call
       (also introduced in Linux 2.1.44 as irix_prctl on the MIPS
       architecture), with prototype

       ptrdiff_t prctl(int option, int arg2, int arg3);

       and  options  to  get  the maximum number of processes per
       user, get the maximum number  of  processors  the  calling
       process  can  use, find out whether a specified process is
       currently blocked, get or  set  the  maximum  stack  size,
       etc., etc.


       The  prctl()  systemcall  was  introduced in Linux 2.1.57.
       There is no prctl() library call as yet.