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From: Paul Emsley <paul.emsley@bioch.ox.ac.uk>
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Subject: execlp
Date: Tue, 22 Nov 2011 16:06:22 +0000
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Hi,

I am trying to see if there is a way to determine if a program is in the 
path (i.e. a bit like "which"), returning a #t or #f answer.  I was 
looking execl and execlp.

The documentation for execl says:

 > Executes the file named by path as a new process image

what is path ?  I'm guessing that that should be "filename".

While playing around, I notice that

(execlp "ls")

produces a core dump.

My question is then, *is* there a way to determine if a string is 
executable? (And if so, how? :-)

Thanks,

Paul.