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- package os2
- /*
- Create an anonymous pipe.
- This procedure creates an anonymous pipe, returning two ends of the pipe, `r`
- and `w`. The file `r` is the readable end of the pipe. The file `w` is a
- writeable end of the pipe.
- Pipes are used as an inter-process communication mechanism, to communicate
- between a parent and a child process. The child uses one end of the pipe to
- write data, and the parent uses the other end to read from the pipe
- (or vice-versa). When a parent passes one of the ends of the pipe to the child
- process, that end of the pipe needs to be closed by the parent, before any data
- is attempted to be read.
- Although pipes look like files and is compatible with most file APIs in package
- os2, the way it's meant to be read is different. Due to asynchronous nature of
- the communication channel, the data may not be present at the time of a read
- request. The other scenario is when a pipe has no data because the other end
- of the pipe was closed by the child process.
- */
- @(require_results)
- pipe :: proc() -> (r, w: ^File, err: Error) {
- return _pipe()
- }
- /*
- Check if the pipe has any data.
- This procedure checks whether a read-end of the pipe has data that can be
- read, and returns `true`, if the pipe has readable data, and `false` if the
- pipe is empty. This procedure does not block the execution of the current
- thread.
- **Note**: If the other end of the pipe was closed by the child process, the
- `.Broken_Pipe`
- can be returned by this procedure. Handle these errors accordingly.
- */
- @(require_results)
- pipe_has_data :: proc(r: ^File) -> (ok: bool, err: Error) {
- return _pipe_has_data(r)
- }
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