added 18.07

git-svn-id: https://svn.eiffel.com/eiffel-org/trunk@2049 abb3cda0-5349-4a8f-a601-0c33ac3a8c38

documentation/18.07/solutions/other-languages/cecil/cecil-samples/cecil-eiffel-c.wiki

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+[[Property:title|CECIL - Eiffel to C]]
+[[Property:weight|1]]
+[[Property:uuid|3d1df3fe-2ac8-1ba3-c846-8329ea8a3772]]
+==array==
+
+This example shows how to create a C array from an existing Eiffel array. 
+
+After you have done the appropriate steps to compile the example, you will get a `cecil.exe` on windows, or `cecil` on Unix. 
+
+Launch the program and you will be prompted for 10 integers that will be inserted in an Eiffel array, it will then initialize the C array and display it. 
+
+A typical output will be:
+<code>
+$ ./cecil
+This example create n array on the Eiffel side and print it on the C side
+Enter 10 integers:
+1
+2
+3
+4
+5
+6
+7
+8
+9
+10
+
+Displaying from C
+@1 = 1
+@2 = 2
+@3 = 3
+@4 = 4
+@5 = 5
+@6 = 6
+@7 = 7
+@8 = 8
+@9 = 9
+@10 = 10
+</code>
+
+==object==
+This example shows the Eiffel memory management and all issues when passing an Eiffel object reference to C. In the example, you can edit the file `root_class.e` to modify the example: 
+<code>
+--give_to_c (o1)
+give_to_c_by_pointer ($o1) -- Choose the way you pass it
+</code>
+When you choose the first possibility (commented by default), give_to_c will use the CECIL API eif_adopt to keep a reference on the Eiffel object. When you choose the second possibility, give_to_c_by_pointer will use the CECIL API eif_protect to keep a reference on the Eiffel object. Until forget_from_c is called from the C side, the object o1 will not be collected since we have protected it through the call to give_to_c or give_to_c_by_pointer. At the end after the object o1 is collected, we try to perform an operation on it which will fail with a call on void target exception. A typical output will be: 
+<code>
+$ cecil
+Creating o1
+Object string is o1
+Give it to C
+Losing reference to initial o1 from Eiffel
+Collecting...
+Display new o1:
+Object string is o2
+Display o1 given to C:
+Object string is o1
+Losing reference from C
+Losing reference from Eiffel
+Collecting...
+An Eiffel object of type OBJECT is collected
+Old o1 forgot from both C and Eiffel:
+Raise a Void exception..
+
+cecil: system execution failed.
+Following is the set of recorded exceptions:
+-------------------------------------------------------------------------------
+Class / Object Routine Nature of exception Effect
+-------------------------------------------------------------------------------
+ROOT_CLASS make @26 display:
+<30068030> Feature call on void target. Fail
+-------------------------------------------------------------------------------
+ROOT_CLASS make @26
+<30068030> Routine failure. Fail
+-------------------------------------------------------------------------------
+ROOT_CLASS root's creation
+<30068030> Routine failure. Exit
+-------------------------------------------------------------------------------
+An Eiffel object of type OBJECT is collected
+</code>
+
+==string==
+This example shows how to create a C string from an existing Eiffel string. After you have done the appropriate steps to compile the example, you will get a `cecil.exe` on windows, or `cecil` on Unix. Launch the program and you will be prompted for a string from Eiffel and a C string will be created and display. A typical output will be: 
+<code>
+$ cecil
+Enter a string to convert into a C string:
+Hello World!
+
+Here is the C string:
+Hello World!
+</code>
+
+
+
+