10-27-2009
Are programs like sys_open( ) ,sys_read( ) et al examples of system level programs ?
Are the programs written on schedulers ,thread library , process management, memory management, et al called systems programs ? How are they different from the programs that implement functions like open() , printf() , scanf() , read() .. they have a prefix sys_open, sys_close, sys_read etc , right ? Is there any difference of hierarchy between the programs that implement system calls and system level programs like that implement thread library, process management , memory managemnt etc..
Hope you understood my qstn
---------- Post updated 10-27-09 at 09:22 PM ---------- Previous update was 10-26-09 at 11:01 PM ----------
I got this cleared ..Here goes the clarification
" Functions like open() , printf() , scanf() , read() are library function implemented on top of their sys_* counterparts so they can be used for any Application development. On the other hand sys_open, sys_close, sys_read etc are implemented as-part-of-system commonly known as kernel. On top of this, system programs like thread library, compilers, linkers are implemented which helps other application development. Hope this clears the difference between system, system programs and application programs. "
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LEARN ABOUT HPUX
sigpause
sigpause(3C) sigpause(3C)
NAME
sigpause - signal management
SYNOPSIS
Obsolescent
DESCRIPTION
The function, along with the and functions provide simplified signal management.
The function removes sig from the calling thread's signal mask and suspends the calling thread until a signal is received. The function
restores the thread's signal mask to its original state before returning.
RETURN VALUE
The function suspends execution of the thread until a signal is received, whereupon it shall return and set to
ERRORS
[EINVAL] sig is not a valid signal number.
WARNINGS
The compiler option must be set to use sigpause(). The use of the function without the option is unspecified.
should not be used in conjunction with signal(2) and sigspace(2).
OBSOLESCENT FUNCTION
will be obsoleted in the near future. The obsolescent function blocks signals according to the value of mask, then atomically waits for an
unmasked signal to arrive. On return, restores the current signal mask to the value that existed before the call. When no signals are to
be blocked, a value of is used for mask.
terminates when it is interrupted by a signal. When terminates, it returns -l and sets to
The obsolescent function is typically used in conjunction with the obsoleted function.
Threads Considerations
Since blocked signal masks are maintained at the thread level, the obsolescent function modifies only the calling thread's blocked signal
mask. suspends only the calling thread until it receives a signal.
If other threads in the process do not block the signal, the signal may be delivered to another thread in the process and the thread in may
continue waiting. For this reason, the use of sigwait(2) is recommended instead of for multi-threaded applications.
For more information regarding signals and threads, refer to signal(5).
LP64 Programs
This obsolescent accepts a long (64 bit) value. However, as for ILP32 programs, supports signals numbered 1 through 32. The upper 32 bits
of the mask argument are ignored.
Author
was developed by the University of California, Berkeley.
SEE ALSO
kill(1), kill(2), pause(2), signal(2), wait(2), abort(3C), setjmp(3C), sighold(3C), sigignore(3C), sigrelse(3C), sigset(3C), signal(5).
STANDARDS CONFORMANCE
sigpause(3C)