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Full Discussion: Strange behaviour with "set -e" and functions
Top Forums Shell Programming and Scripting Strange behaviour with "set -e" and functions Post 302335454 by tokland on Sunday 19th of July 2009 12:00:44 PM
Old 07-19-2009
Strange behaviour with "set -e" and functions
Hi,

This seems to be a recurrent problem on mailing lists and bug reports, but I've been unable to find a solution. Let's imagine we have this bash script:

Code:
#!/bin/bash
set -e

fun() {
  echo "fun_start"
  test 1 = 2 
  echo "fun_end"
}

echo "main_start"
fun 
echo "main_end"

This outputs:

Code:
main_start
fun_start

Right, but now I want the script to continue if "fun" fails, so I protect it with a "||":

Code:
echo "main_start"
fun || echo "fun failed"
echo "main_end"

And that's what I get (!):

Code:
main_start
fun_start
fun_end
main_end

The function continues even though there has been an error and my conditional statement is not even run. It seems that "set -e" is being ignored inside the function. That seems very counterintuitive. The only solution I found was adding "|| return 1" to every "dangerous" call inside a function, but then what's the point of using set -e?

So, am I doing something wrong? is there any easy way to get this desired output?

Code:
main_start
fun_start
fun failed
main_end

thanks
 

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LEARN ABOUT OPENSOLARIS

libbash

LIBBASH(7)							  libbash Manual							LIBBASH(7)

NAME

     libbash -- A bash shared libraries package.

DESCRIPTION

     libbash  is  a package that enables bash dynamic-like shared libraries. Actually its a tool for managing bash scripts whose functions you may
     want to load and use in scripts of your own.

     It contains a 'dynamic loader' for the shared libraries ( ldbash(1)), a configuration tool (ldbashconfig(8)), and some libraries.

     Using ldbash(1) you are able to load loadable bash libraries, such as getopts(1) and hashstash(1).  A bash shared library that can be  loaded
     using
     ldbash(1) must answer 4 requirments:

     1.     It must be installed in $LIBBASH_PREFIX/lib/bash (default is /usr/lib/bash).

     2.     It must contain a line that begins with '#EXPORT='.  That line will contain (after the '=') a list of functions that the library
	    exports.  I.e. all the function that will be usable after loading that library will be listed in that line.

     3.     It must contain a line that begins with '#REQUIRE='.  That line will contain (after the '=') a list of bash libraries that are
	    required for our library.  I.e. every bash library that is in use in our bash library must be listed there.

     4.     The library must be listed (For more information, see ldbashconfig(8)).

   Basic guidelines for writing library of your own:
     1.     Be aware, that your library will be actually sourced. So, basically, it should contain (i.e define) only functions.

     2.     Try to declare all variables intended for internal use as local.

     3.     Global variables and functions that are intended for internal use (i.e are not defined in '#EXPORT=') should begin with:
		  __<library_name>_
	    For example, internal function myfoosort of hashstash library should be named as
		  __hashstash_myfoosort
	    This helps to avoid conflicts in global name space when using libraries that come from different vendors.

     4.     See html manual for full version of this guide.

AUTHORS

     Hai Zaar <haizaar@haizaar.com>
     Gil Ran <ril@ran4.net>

SEE ALSO

     ldbash(1), ldbashconfig(8), getopts(1), hashstash(1) colors(1) messages(1) urlcoding(1) locks(1)

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