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Get additional information about a message
#include <sys/neutrino.h> int MsgInfo( int rcvid, struct _msg_info* info ); int MsgInfo_r( int rcvid, struct _msg_info* info );
- The return value from MsgReceive*().
- A pointer to a _msg_info structure where the function can store information about the message.
Use the -l c option to qcc to link against this library. This library is usually included automatically.
The MsgInfo() and MsgInfo_r() kernel calls get additional information about a received message and store it in the specified _msg_info structure.
These functions are identical, except in the way they indicate errors. See the Returns section for details.
|The info->msglen and info->srcmsglen members are valid only until the next call to MsgRead*() or MsgWrite*().|
This call doesn't block.
The only difference between these functions is the way they indicate errors:
- If an error occurs, -1 is returned and errno is set. Any other value returned indicates success.
- EOK is returned on success. This function does NOT set errno. If an error occurs, any value in the Errors section may be returned.
- A fault occurred when the kernel tried to access the buffers provided.
- The thread indicated by rcvid doesn't exist.