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wxMaxima
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A second connection from Maxima's Lisp that interrupts its computation. More...
#include <MaximaInterruptChannel.h>
Public Member Functions | |
| MaximaInterruptChannel (wxSocketBase *socket, const wxString &token) | |
Takes ownership of socket, a connection wxSocketServer::Accept() returned. | |
| bool | IsReady () const |
| True once the connection has proved it comes from our Maxima, and while it lasts. | |
| bool | IsDead () const |
| True once the connection failed the handshake or was closed. | |
| bool | SendInterrupt () |
| Asks Maxima to interrupt its computation. Returns false if that isn't possible. | |
A second connection from Maxima's Lisp that interrupts its computation.
Interrupting Maxima used to rely on the operating system: kill(SIGINT) on POSIX, and on MS Windows a shared-memory segment named after the Lisp's pid or, failing that, a console Ctrl+C. The Windows ways fail in ways a user can do nothing about (GH #2289): the pid may be unknown, the segment is only created if Maxima's signal thread was started, and wxmaxima.exe has no console.
So a Lisp that has threads opens a second connection to wxMaxima's server right after connecting (wx-open-interrupt-channel in wxMathML.lisp). A thread in the Lisp waits on it, and SendInterrupt() writing "interrupt" makes that thread interrupt the one evaluating Maxima's commands. A Lisp without threads never opens one; IsReady() then stays false and the caller falls back to the old ways.
The connection only counts after it has sent the secret wxMaxima gave Maxima (see InterruptChannelHandshake): anybody on this machine can connect to the server's port.
| MaximaInterruptChannel::MaximaInterruptChannel | ( | wxSocketBase * | socket, |
| const wxString & | token | ||
| ) |
Takes ownership of socket, a connection wxSocketServer::Accept() returned.
| token | The secret the connection has to send first. |
1.9.6