I am using HPUX on Itanium and I have c program where I am doing something like this
but this pthread_create always fails at runtime
prio = PRI_MAX;
prio_low = PRI_MIN;
.
.
.
.
struct sched_param sched_param={1};
sched_param.sched_priority=prio;
thret = pthread_attr_setschedparam(&serv_attr, &sched_param);

thret = pthread_attr_setinheritsched(&serv_attr,PTHREAD_EXPLICIT_SCHED);

.
.
.
thret = pthread_create(&sthread,&serv_attr,server_main, 0);

but if i remove this line

thret = pthread_attr_setinheritsched(&serv_attr,PTHREAD_EXPLICIT_SCHED);

it works fine, can anyone suggest whats happening here. I have tried the same on AIX and Solaris, it works there.

I have never played with the scheduling calls on any unix, but I will make a guess. Look at the man page for rtsched() and notice the following routines:
sched_get_priority_max()
sched_get_priority_min()
PRI_HPUX_TO_POSIX()
PRI_POSIX_TO_HPUX()
My guess is that some combination of these routines is needed. Priorities on HP-UX are backwards. Or reversed. Or mirror-imaged. Or something like that. Anyway, it looks like a landmine waiting to be stepped on:It has never been clear to me which routines use which style of priority. I just take the OS defaults on priority so I don't really care. If you get this working, please let us know the secret.

NAME
rtsched - execute process with real-time priority

SYNOPSIS
rtsched -s scheduler -p priority command [arguments]

rtsched [ -s scheduler ] -p priority -P pid

DESCRIPTION
Rtsched executes command with POSIX or HP-UX real-time priority, or
changes the real-time priority of currently executing process pid.
----------------------------------------------------------------------------

this is what I found when I checked the man page of the rtsched. This basically tells about the process scheduling on HP-UX.
And my program illustrated above only playing with the standard pthreads.
Can you put more focus on this.
I did not get what you wanted to suggest.
Please respond and correct me if I am wrong here.

Your man page must be truncated somehow. Mine has a lot more than you quote. This includes descriptions of the functions I mentioned and that quote I have above came from the man page as well. Try this copy rtsched(2).