QNX Developer Support
|This version of this document is no longer maintained. For the latest documentation, see http://www.qnx.com/developers/docs.|
Unblock a client and set its errno
#include <sys/neutrino.h> int MsgError( int rcvid, int error ); int MsgError_r( int rcvid, int error );
- The receive ID that MsgReceive*() returned.
- The error code that you want to set for the client.
Use the -l c option to qcc to link against this library. This library is usually included automatically.
The MsgError() and MsgError_r() kernel calls unblock the client's MsgSend*() call and set the client's errno to error. No data is transferred.
If error is EOK, the MsgSend*() call returns EOK; if error is any other value, the MsgSend*() call returns -1.
These functions are identical except in the way they indicate errors. See the Returns section for details.
|An error number of ERESTART causes the sender to immediately call MsgSend*() again. Since send and reply buffers passed to MsgSend() may overlap, you shouldn't use ERESTART after a call to MsgWrite().|
None. In the network case, lower priority threads may run.
MsgError() has increased latency when you use it to communicate across a network -- the server is now writing the error code to its local npm-qnet, which may need to communicate with the client's npm-qnet to actually transfer the error code.
The only difference between these functions is the way they indicate errors:
- If an error occurs, the function returns -1 and and sets errno. Any other value returned indicates success.
- Returns EOK on success. This function does NOT set errno. If an error occurs, the function returns one of the values listed in the Errors section.
- The thread indicated by rcvid doesn't exist.