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Diffstat (limited to 'doc')
| -rw-r--r-- | doc/chan.n | 12 |
1 files changed, 12 insertions, 0 deletions
@@ -547,6 +547,18 @@ this, spawn with "2>@" or ">@" redirection operators onto the write side of a pipe, and then immediately close it in the parent. This is necessary to get an EOF on the read side once the child has exited or otherwise closed its output. +.RS +.PP +Note that the pipe buffering semantics can vary at the operating system level +substantially; it is not safe to assume that a write performed on the output +side of the pipe will appear instantly to the input side. This is a +fundamental difference and Tcl cannot conceal it. The overall stream semantics +\fIare\fR compatible, so blocking reads and writes will not see most of the +differences, but the details of what exactly gets written when are not. This +is most likely to show up when using pipelines for testing; care should be +taken to ensure that deadlocks do not occur and that potential short reads are +allowed for. +.RE .VE 8.6 .TP \fBchan pop \fIchannelId\fR |