diff options
| author | andreas_kupries <akupries@shaw.ca> | 2010-03-03 18:30:26 (GMT) |
|---|---|---|
| committer | andreas_kupries <akupries@shaw.ca> | 2010-03-03 18:30:26 (GMT) |
| commit | 4a7184ccc431e5e65151b8bccee62179269d099e (patch) | |
| tree | a2b9633a7d406519fff79a51bd1cf6001573f116 /doc/refchan.n | |
| parent | 618503676d9bd1174c263775d6a2aeef4a838ae1 (diff) | |
| download | tcl-4a7184ccc431e5e65151b8bccee62179269d099e.zip tcl-4a7184ccc431e5e65151b8bccee62179269d099e.tar.gz tcl-4a7184ccc431e5e65151b8bccee62179269d099e.tar.bz2 | |
* doc/refchan.n: Followup to ChangeLog entry 2009-10-07
(generic/tclIORChan.c). Fixed the documentation to explain that
errno numbers are operating system dependent, and reworked the
associated example.
Diffstat (limited to 'doc/refchan.n')
| -rw-r--r-- | doc/refchan.n | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/doc/refchan.n b/doc/refchan.n index b3ad232..4edd7ad 100644 --- a/doc/refchan.n +++ b/doc/refchan.n @@ -4,7 +4,7 @@ '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" -'\" RCS: @(#) $Id: refchan.n,v 1.18 2010/01/14 18:13:12 dkf Exp $ +'\" RCS: @(#) $Id: refchan.n,v 1.19 2010/03/03 18:30:28 andreas_kupries Exp $ .so man.macros .TH refchan n 8.5 Tcl "Tcl Built-In Commands" .BS @@ -132,8 +132,11 @@ error EAGAIN .PP For extensibility any error whose value is a negative integer number will cause the higher layers to set the C-level variable "\fBerrno\fR" -to the absolute value of this number, signaling a system error. This -means that both +to the absolute value of this number, signaling a system error. +However, note that the exact mapping between these error numbers and +their meanings is operating system dependent. +.PP +For example, while on Linux both .PP .CS return -code error -11 @@ -143,8 +146,12 @@ and error -11 .CE .PP -are equivalent to the examples above, using the more readable string "EAGAIN". -No other error value has such a mapping to a symbolic string. +are equivalent to the examples above, using the more readable string "EAGAIN", +this is not true for BSD, where the equivalent number is -35. +.PP +The symbolic string however is the same across systems, and internally +translated to the correct number. No other error value has such a mapping +to a symbolic string. .PP If the subcommand throws any other error, the command which caused its invocation (usually \fBgets\fR, or \fBread\fR) will appear to have |