Re: [Cdw-devel] UDF Create & Write Image Support within CDW

[Roger <rog...@gm...>]

>Well, looks... complicated :)

Yup.. What I hate about programming.  It's easy if you yourself writes the 
code, but if somebody wants to contribute, they have to read & understand the 
(book of) code to further add to it. ;-)


>If memory serves me well, I was able to create an ISO image file with just one 
>(or maybe two) command executed with exec(), and here we have a series of 
>commands to be executed in sequence. One of them also depends on user being 
>able to successfully run commands with sudo without the need to provide user 
>password.
>
>It surely could be done, and in first implementation I could just 
>somehow* capture return value from a command to only get its 
>success/failure status, to know whether I can execute the next command 
>in sequence. Maybe later on I could also capture some error messages 
>printed to stdout/stderr to learn why a command has failed.
>
>Complicated, but probably doable :)
>
>*) maybe I could get this value through environment variable described 
>in man exec(3), or maybe I should execute these commands with system(). 
>Learning how to get value returned by executed commands should be the 
>first thing to do when implementing the procedure you described.

A quick search on Google reveals,
"C - How can i get return value of command passed to execl?"
http://stackoverflow.com/questions/2667095/c-how-can-i-get-return-value-of-command-passed-to-execl

Likely a very popular and already thought out solution to this one.

A second result shows,
"how can I get the return value of a program executed by exec?"
http://stackoverflow.com/questions/3776859/how-can-i-get-the-return-value-of-a-program-executed-by-exec

call_shell_cmd (or exec_shell_cmd)
call_shell_cmd_returnval (or exec_shell_cmd_returnval)

I thought you were already calling some shell commands within the CDW code, as 
you could already configure CDW to use custom commands?

-- 
Roger
http://rogerx.freeshell.org/