.TH NDBUF_WRITE_RAW 3 "15 September 2018" "NDBUF" "Binary buffers lib manual"
.SH NAME
ndbuf_write_u8, ndbuf_write_u16, ndbuf_write_u32, ndbuf_write_u64, 
ndbuf_write_raw - write data to the buffer of specified length and type
.SH SYNOPSIS
.B "#include <ndbuf/ndbuf.h>"
.PP
.nf
uint32_t ndbuf_write_u8(ndbuf_t *b, uint8_t val);
uint32_t ndbuf_write_u16(ndbuf_t *b, uint16_t val);
uint32_t ndbuf_write_u32(ndbuf_t *b, uint32_t val);
uint32_t ndbuf_write_u64(ndbuf_t *b, uint64_t val);
uint32_t ndbuf_write_raw(ndbuf_t *b, void *src, uint32_t len);
.fi
.SH DESCRIPTION
The ndbuf_write_ family writes data to an
.B ndbuf_t
instance from caller-provided storage. On success each function returns the number of bytes written; on error it returns 0.

.TP
.B ndbuf_write_u8(ndbuf_t *b, uint8_t val)
Write one unsigned 8‑bit value to the current buffer position from
.I val
and advance the buffer cursor by one byte. Returned value is the number of bytes written (1) or 0 on error.

.TP
.B ndbuf_write_u16(ndbuf_t *b, uint16_t val)
Writes one unsigned 16‑bit value, from
.I val
and advance the cursor by two bytes. Returns 2 on success or 0 on error.

.TP
.B ndbuf_write_u32(ndbuf_t *b, uint32_t val)
Write one unsigned 32‑bit value, from
.I val
and advance the cursor by four bytes. Returns 4 on success or 0 on error.

.TP
.B ndbuf_write_u64(ndbuf_t *b, uint64_t val)
Write one unsigned 64‑bit value, from
.I val
and advance the cursor by eight bytes. Returns 8 on success or 0 on error.

.TP
.B ndbuf_read_raw(ndbuf_t *b, void *dst, uint32_t len)
Copy
.I len
from
.I dst
to the buffer and advance the cursor by
.I len. The caller must ensure
.I dst
points to memory at least
.I len
bytes long. Returns the number of bytes copied or 0 on error.
.SH RETURN VALUE
On success each function returns the number of bytes read. On error they return 0; no specific
.I errno
value is set.
.SH ERRORS
Functions return 0 when the requested read would exceed the available data, when
.I b
is NULL, or on other internal errors. Callers must validate the return value before using output data.
.SH RATIONALE
None
.SH EXAMPLES
None
.PP
.SH SEE ALSO
.BR ndbuf_read_raw(3),
.BR ndbuf_print(3)
.SH COPYRIGHT
This software licensed under GNU LGPL v2.1 or later. See COPYING for further details.
.PP
(c) Authors of libndbuf 2017-2018 <http://vapaa.xyz>
.SH AUTHOR
Alexander Vdolainen (alex@vapaa.xyz)