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