net, os, syscall: Plan 9: adjust error handling
syscall: Use NewError for all system errors and introduce
some new errors for compatibility with other packages
and proper error handling in net. Also introduce
Temporary and Timeout methods on ErrorString.
net: Make errors from dial, accept, listen functions follow the
OpError standard and discern whether the underlying
error came from syscall. Since Plan 9 uses a correspondence
between file and network operations, all system error
reporting happens through the underlying file operation.
In Go code, we go through package os for file operations,
so there is another level of indirection in error types.
This change allows us to compare the errors with those in
package syscall, when appropriate.
os: Just use the error string already present in package os,
instead of calling out to package syscall.
R=rsc, ality, rminnich, bradfitz
CC=golang-dev
https://golang.org/cl/
7398054