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Full Discussion: How i use pointer as a string in c programing?
Top Forums Programming How i use pointer as a string in c programing? Post 302708325 by Corona688 on Monday 1st of October 2012 11:29:50 AM
Old 10-01-2012
Quote:
Originally Posted by raihan004
but without declaring arry its work on windows how and why?
By complete coincidence, nothing more. If this was a debug build, a release build might crash, or vice versa. You are using undefined behavior -- undefined doesn't mean "will crash", undefined means "unpredictable".

Windows will let you get away with very stupid things -- temporarily. It allowed me to delete my video surface sixty times per second and not crash then and there. It still crashed, but far later, in mysterious ways which took days to debug, because not crashing immediately meant I had no clue where the bug was.

Using undefined memory means you're wrecking something, somewhere. You might be overwriting your stack pointer, wrecking your ability to make function calls. You might be overwriting something in heap space, ruining heap pointers and causing weird malloc() crashes later. You might be in data space and overwriting your global variables. This is not safe, stable, or sane. Memory does not work that way. Use a buffer.
Last edited by Corona688; 10-01-2012 at 12:39 PM..
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LEARN ABOUT OPENSOLARIS

savecore

savecore(1M)						  System Administration Commands					      savecore(1M)

NAME

       savecore - save a crash dump of the operating system

SYNOPSIS

       /usr/bin/savecore [-Lvd] [-f dumpfile] [directory]

DESCRIPTION

       The  savecore  utility saves a crash dump of the kernel (assuming that one was made) and writes a reboot message in the shutdown log. It is
       invoked by the dumpadm service each time the system boots.

       savecore saves the crash dump data in the file directory/vmcore.n and the kernel's namelist in directory/unix.n. The  trailing  .n  in  the
       pathnames is replaced by a number which grows every time savecore is run in that directory.

       Before writing out a crash dump, savecore reads a number from the file directory/minfree. This is the minimum number of kilobytes that must
       remain free on the file system containing directory. If after saving the crash dump the file system containing directory  would	have  less
       free  space the number of kilobytes specified in minfree, the crash dump is not saved. if the minfree file does not exist, savecore assumes
       a minfree value of 1 megabyte.

       The savecore utility also logs a reboot message using facility LOG_AUTH (see syslog(3C)). If the system crashed as a  result  of  a  panic,
       savecore logs the panic string too.

OPTIONS

       The following options are supported:

       -d	      Disregard  dump  header  valid flag. Force savecore to attempt to save a crash dump even if the header information stored on
		      the dump device indicates the dump has already been saved.

       -f dumpfile    Attempt to save a crash dump from the specified file instead of from the system's current dump device. This  option  may	be
		      useful if the information stored on the dump device has been copied to an on-disk file by means of the dd(1M) command.

       -L	      Save  a  crash  dump  of the live running Solaris system, without actually rebooting or altering the system in any way. This
		      option forces savecore to save a live snapshot of the system to the dump device, and then immediately to retrieve  the  data
		      and  to  write  it out to a new set of crash dump files in the specified directory. Live system crash dumps can only be per-
		      formed if you have configured your system to have a dedicated dump device using dumpadm(1M).

		      savecore -L does not suspend the system, so the contents of memory continue to change while the dump is  saved.  This  means
		      that live crash dumps are not fully self-consistent.

       -v	      Verbose. Enables verbose error messages from savecore.

OPERANDS

       The following operands are supported:

       directory    Save  the  crash  dump files to the specified directory. If directory is not specified, savecore saves the crash dump files to
		    the default savecore directory, configured by dumpadm(1M).

FILES

       directory/vmcore.n

       directory/unix.n

       directory/bounds

       directory/minfree

       /var/crash/'uname -n'	    default crash dump directory

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       adb(1), mdb(1), svcs(1), dd(1M), dumpadm(1M), svcadm(1M), syslog(3C), attributes(5), smf(5)

NOTES

       The system crash dump service is managed by the service management facility, smf(5), under the service identifier:

	 svc:/system/dumpadm:default

       Administrative actions on this service, such as enabling, disabling, or requesting restart, can be performed  using  svcadm(1M).  The  ser-
       vice's status can be queried using the svcs(1) command.

       If the dump device is also being used as a swap device, you must run savecore very soon after booting, before the swap space containing the
       crash dump is overwritten by programs currently running.

SunOS 5.11							    25 Sep 2004 						      savecore(1M)
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