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problem implementing fork

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Top Forums Programming problem implementing fork
# 8  
Old 10-11-2009
A couple of things come to mnd....
  1. I'd use something other than SIGALRM to signal the parent. Perhaps SIGCHLD or SIGUSR1
  2. Forking gives the parent the opportunity to do something useful if the kid hangs. For instance, if the I/O subsystem were to be unable to complete an i/o and fail to return an error on a Solaris (or any system using DMA for I/O) , the kid will be unkillable and hang. This is because you might remove the process memory, reallocate it to another process only to have the DMA device complete the physical i/o. It might be useful to tell someone about the i/o issue via a timeout mechanism.
  3. Is forking all that expensive in a Linux system? Most everything except for the LWP stuff will be created with either model. The forking model makes expansion of the code to handle multiple tasks saner..

sorry about the late reply...
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linux-version

LINUX-VERSION(1)					      General Commands Manual						  LINUX-VERSION(1)

NAME

       linux-version - operate on Linux kernel version strings

SYNOPSIS

       linux-version compare VERSION1 OP VERSION2

       linux-version sort [--reverse] [VERSION1 VERSION2 ...]

       linux-version list [--paths]

DESCRIPTION

       linux-version operates on Linux kernel version strings as reported by uname -r and used in file and directory names.  These version strings
       do not follow the same rules as Debian package version strings and should not be compared as such or as arbitrary strings.

       compare VERSION1 OP VERSION2
	      Compare version strings, where OP is a binary operator. linux-version returns success (zero result) if the  specified  condition	is
	      satisfied, and failure (nonzero result) otherwise.  The valid operators are: lt le eq ne ge gt

       sort [--reverse] [VERSION1 VERSION2 ...]
	      Sort the given version strings and print them in order from lowest to highest.  If the --reverse option is used, print them in order
	      from highest to lowest.

	      If no version strings are given as arguments, the version strings will instead be read from standard input, one per line.  They  may
	      be suffixed by arbitrary text after a space, which will be included in the output.  This means that, for example:

	      linux-version list --paths | linux-version sort --reverse

	      will list the installed versions and corresponding paths in order from highest to lowest version.

       list [--paths]
	      List kernel versions installed in the customary location.  If the --paths option, show the corresponding path for each version.

AUTHOR

       linux-version and this manual page were written by Ben Hutchings as part of the Debian linux-base package.

								   30 March 2011						  LINUX-VERSION(1)