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.\" Copyright © 2002 - Philip Howard - All rights reserved
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.TH vrb_write_min 3 2002-09-30 vrb "VRB Programmer's Manual"
.SH NAME
vrb_write_min - write data from a VRB
.SH LIBRARY
.B -lvrb
.SH SYNOPSIS
.B #include <vrb.h>
.sp
.IB "size_t " "vrb_write_min" "(vrb_p " "vrb" ", int " "fd" ", size_t " "maxsize" ", size_t " "minsize" ");"
.SH DESCRIPTION
.B vrb_write_min
writes a minimum amount of data to a specified open file descriptor
using
.B write(2)
from the specified
virtual ring buffer until the specified maximum length has been written,
the buffer is full, or an error is returned
(including EAGAIN or EWOULDBLOCK for a non-blocking descriptor).
If there is insufficient data in the buffer to write the minimum amount,
then
.B write(2)
will not be called.
.SH ARGUMENTS
.IB "vrb_p " vrb
.br
specifies which virtual ring buffer.
.sp
.IB "int " fd
.br
specifies the open file descriptor to write to
.sp
.IB "size_t " maxsize
.br
specifies the maximum length to write, or
.B "~0"
for unlimited.
.sp
.IB "size_t " minsize
.br
specifies the minimum length to write.
.SH "RETURN VALUE"
.I size_t
.br
If successful, the actual length of data written from the buffer is returned.
If the minimum amount of data was not available to be written,
0 is returned.
If an error occurs from
.B write(2),
the return value is ~0 and
errno is set by
.B write(2).
.SH ERRORS
If an error is returned, then
.I errno
will have one of the following values:
.TP
.B 0
An end-of-file has occurred.
Note that this is a different way of returning an end-of-file
condition than
.B write(2)
uses.
.TP
.B EINVAL
An invalid virtual ring buffer pointer was specified.
.SH "SEE ALSO"
.BR vrb (3),
.BR vrb_capacity (3),
.BR vrb_data_len (3),
.BR vrb_data_ptr (3),
.BR vrb_destroy (3),
.BR vrb_get (3),
.BR vrb_get_min (3),
.BR vrb_give (3),
.BR vrb_init (3),
.BR vrb_init_opt (3),
.BR vrb_is_empty (3),
.BR vrb_is_full (3),
.BR vrb_is_not_empty (3),
.BR vrb_is_not_full (3),
.BR vrb_move (3),
.BR vrb_new (3),
.BR vrb_new_opt (3),
.BR vrb_put (3),
.BR vrb_put_all (3),
.BR vrb_read (3),
.BR vrb_read_min (3),
.BR vrb_resize (3),
.BR vrb_space_len (3),
.BR vrb_space_ptr (3),
.BR vrb_take (3),
.BR vrb_uninit (3),
.BR vrb_write (3),
.BR write(2)