To my knowledge, the system provides no such call. At best, you can "unread" what you read by seeking back, or by playing with the buffers.

Update: Actually, linux provides pread: "Read from a file descriptor at a given offset. The file offset is not changed." I don't see any existing modules providing access to it, though. It requires a seekable handle.

In reply to Re: preview a filehandle's next character WITHOUT changing the position of the handle by ikegami
in thread preview a filehandle's next character WITHOUT changing the position of the handle by chengj86

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