Capturing a ret val of C obj file in ksh script

Applications Programming
1

Hi,

I have one shell script which is calling a C executable. That C executable returns a value depending upon operations inside the C code. But how to get that value in the calling shell script?

The syntax of calling the C executable is like --
C_exec <argc no> <argument1> <argument2> etc ...

When I am doing
return_value=C_exec <argc no> <argument1> <argument2> etc ...

The runtime error is shown as --
<argc no>: not found

Pls help.

Bijitesh

2

Something like...

/path/to/C_exec <argc no> <argument1> <argument2>
return_value=$?
3

if your value is between 0-255 simply use
exit( ret ); in your c-code. echo $? is the exitcode of the last cmd and your value.

4

The return status (what you want) is stored in the $? variable

/path/to/C_exec <argc no> <argument1> <argument2>
retval=$?
if [ $retval -eq 0 ] ; then
  echo "success"
else
  echo "failure"
fi

This test is for a simple 0 = success, anything else = failure

5

Thanks vino for ur reply. But that syntax is not working.
Instead grumpf's suggestion is working. Thanks grumpf and jim mcnamara.

My problem is solved. But, just out of curiosity, I want to know the way of returning a character string or simply a character from C executable to calling shell script.

Thanks in advance,
Bijitesh

6

The exit code mechanism is working basicly since main() is int. What you see on shell is the return
code of main() (using void main() is therefore a BAD idea).
A string is something different. The easy way retvar=$( myprg ) works only IFF there is no
other output.