Open System Services System Calls Reference Manual (G06.29+, H06.08+, J06.03+)

spt_writevx(2) OSS System Calls Reference Manual
• If the O_NONBLOCK flag is set, the spt_writevx() function returns the value -1 and
errno is set to [EAGAIN].
When you attempt to write to a socket with no space available for data:
• If the O_NONBLOCK flag is not set, the spt_writevx() function blocks until space
becomes available.
• If the O_NONBLOCK flag is set, the spt_writevx() function returns the value -1 and
sets errno to [EAGAIN]. The O_NONBLOCK flag has no effect if space is available.
Upon successful completion, the spt_writevx() function marks the st_ctime and st_mtime fields
of the file for update and clears the set-user-ID and set-group-ID attributes if the file is a regular
file.
The spt_fcntlx() function provides more information about record locks.
If it is interrupted by a signal before it writes any data, the spt_writevx() function returns the
value -1 with errno set to [EINTR]. If it is interrupted by a signal after it has successfully written
some data, the spt_writevx() function returns the number of bytes that it has written.
Use on Guardian Objects
Attempting to write to a Guardian file (that is, a file in /G) that is locked causes the
spt_writevx() function to return -1 and set errno to [EGUARDIANLOCKED].
NOTES
For C applications, a macro to map writev() to spt_writevx() is available when you use the
#define SPT_THREAD_AWARE_NONBLOCK preprocessor directive before including
spthread.h or when you use an equivalent compiler command option to compile the application.
For C++ applications, an alias to map writev( ) to spt_writevx() is available when you use the
#define SPT_THREAD_AWARE_PRAGMA_NONBLOCK preprocessor directive before
including spthread.h or when you use an equivalent compiler command option to compile the
application.
RETURN VALUES
Upon successful completion, the spt_writevx() function returns the number of bytes that were
actually written. Otherwise, the value -1 is returned, and errno is set to indicate the error.
If the file descriptor becomes invalid (is closed by another thread), -1 is returned with an errno
value of [EBADF]. If a signal is received via the pthread_kill() function and is not blocked,
ignored, or handled, -1 is returned with an errno value of [EINTR].
ERRORS
If any of these conditions occur, the spt_writevx() function sets errno to the corresponding
value:
[EAGAIN] One of these conditions occurred:
• An attempt was made to write to a file descriptor that cannot accept data,
and the O_NONBLOCK flag is set.
• A write to a pipe (FIFO file) of PIPE_BUF bytes or less is requested,
O_NONBLOCK is set, and not enough free space is available.
• The O_NONBLOCK flag is set on this file, and the process would be
delayed in the write operation.
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