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resmgr_msgwritev()
Write a message to a client

QNX Momentics IDE User's Guide
This User's Guide describes version 8.0 of the Integrated Development Environment (IDE) that's part of the QNX Tool Suite.
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QNX SDP is a cross-compiling and debugging environment, including an IDE and command-line tools, for building binary images and programs for target boards running the QNX OS 8.0.
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        Reply to a client with a message, endian-swapping if required
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        Write a message to a client
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        Write a message to a client
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resmgr_msgwritev()

QNX SDP8.0C Library ReferenceAPIDeveloper

Write a message to a client

Synopsis:

#include <sys/iofunc.h>
#include <sys/resmgr.h>

ssize_t resmgr_msgwritev( resmgr_context_t *ctp,
                          const iov_t *smsg,
                          int sparts,
                          size_t offset );

Arguments:

ctp: A pointer to a resmgr_context_t structure that the resource-manager library uses to pass context information between functions. This function extracts the rcvid from this structure.
smsg: An array of buffers that contains the data you want to write.
sparts: The number of elements in the array. This function doesn't let you write past the end of the sender's buffer; it returns the number of bytes actually written.
offset: An offset into the sender's buffer that indicates where you want to start writing the data.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The resmgr_msgwritev() function is a cover function for MsgWritev(), and performs the exact same functionality. It's provided for consistency with resmgr_msgwrite().

Note:

As a client may have overlapping send and reply buffers, you must complete all MsgRead*() operations from a particular send (i.e. particular rcvid) before initiating any MsgWrite*() operations to that client.

Returns:

The number of bytes written, or -1 if an error occurred (errno is set).

Errors:

EFAULT: A fault occurred in the sender's address space when a server tried to access the sender's return message buffer.
EOVERFLOW: The sum of the IOV lengths exceeds SSIZE_MAX, or the number of parts exceeds 524288.
ESRCH: The thread indicated by ctp->rcvid doesn't exist or has had its connection detached.
ESRVRFAULT: A fault occurred when the kernel tried to access the buffers provided.

Classification:


Safety:
Cancellation point	No
Signal handler	Yes
Thread	Yes

Page updated: August 11, 2025