How the stream capture is implemented¶
The three standard streams stdout, stderr and stdin are basically FILE handles that have specific behaviours, writing to any of these stream is same as writing to a file opened with the function fopen.
When a stream is captured in in libcester a new temporary text file with the name as the address of that stream is created in a temporary folder. The temporary folder varies across various operating systems, the default location on windows is determined by the return value of getenv(“TEMP”) if not set the folder “C:/libcester_tmp/” is used. On other platforms the value of getenv(“TMPDIR”) is used and if not set the fallback folder is “/tmp/libcester_tmp/”.
At the point of capture the stream variable is updated to point to the stream address of the new text file created in the temporary folder, the actual address of the stream is cached in the stream_capture_object and at the point of stream release the created file is closed and deleted and the stream variable is updated to point to the original stream address cached in the stream_capture_object.
The file is opened with the the create + write mode w+, on reset the file handle is closed and reopened with the w+ mode. The handle is kept open until the stream is released, so it important to always release captured streams.