ndbuf_setflags manual has been added;

man/Makefile.am

@@ -4,5 +4,5 @@ man_MANS = ndbuf_new.3 ndbuf_new_palloc.3 ndbuf_new_wmops.3 ndbuf_new_frombuf.3
 	ndbuf_write_u32.3 ndbuf_write_u64.3 ndbuf_write_raw_head.3 ndbuf_escan.3 \
 	ndbuf_escan_va.3 ndbuf_escan_wot.3 ndbuf_print.3 ndbuf_print_va.3 ndbuf_print_wot.3 \
 	ndbuf_length.3 ndbuf_alength.3 ndbuf_leftlength.3 ndbuf_setlength.3 ndbuf_rdata.3 \
-	ndbuf_rdatacur.3 ndbuf_resetcur.3
+	ndbuf_rdatacur.3 ndbuf_resetcur.3 ndbuf_setflags.3 ndbuf_exflags.3 ndbuf_flagsreset.3
 

man/ndbuf_exflags.3

@@ -0,0 +1 @@
+ndbuf_setflags.3

man/ndbuf_flagsreset.3

@@ -0,0 +1 @@
+ndbuf_setflags.3

man/ndbuf_setflags.3

@@ -0,0 +1,83 @@
+.TH NDBUF_SETFLAGS 3 "28 October 2021" "NDBUF" "Binary buffers library manual"
+
+.SH NAME
+ndbuf_setflags, ndbuf_exflags, ndbuf_flagsreset - manage flags controlling ndbuf behaviour
+
+.SH SYNOPSIS
+.nf
+#include <ndbuf/ndbuf.h>
+
+void ndbuf_setflags(ndbuf_t *b, int flags);
+void ndbuf_exflags(ndbuf_t *b, int flags);
+
+#define ndbuf_flagsreset(a) ndbuf_exflags((a), 0)
+.nf
+
+.SH LIBRARY
+libndbuf
+
+.SH DESCRIPTION
+These functions manipulate the flags associated with an ndbuf_t instance. Flags control behavioural aspects such as zero-copy/copyless operation, burn semantics, read/write permissions, and other implementation-specific options. See SUPPORTED FLAGS.
+
+.IP "\fBvoid ndbuf_setflags(ndbuf_t *b, int flags)\fR"
+Set the buffer's flags to the provided flags value. This replaces the current flag set with flags. Use this when you want to explicitly assign a new flags mask.
+
+.IP "\fBvoid ndbuf_exflags(ndbuf_t *b, int flags)\fR"
+Exchange (apply) flags with the buffer; semantics are implementation-dependent but commonly used to modify or merge flags. In libndbuf this function is used to set flags while optionally returning or replacing previous flags state (check the header/source for exact behavior). Typically exflags will update the buffer's flags to flags; callers expecting previous flags should obtain them via the appropriate accessor if available.
+
+.IP "\fB#define ndbuf_flagsreset(a) ndbuf_exflags((a), 0)\fR"
+Reset all flags on the buffer by calling ndbuf_exflags with 0. This macro provides a convenient way to clear all flag bits.
+
+.SH SUPPORTED FLAGS
+.IP "\fBNDBUF_BURN\fR"
+Burn data before freeing.
+
+.IP "\fBNDBUF_NREA\fR"
+Make the data buffer non-reallocatable.
+
+.IP "\fBNDBUF_UCMD\fR"
+Buffer with custom memory operations provided.
+
+.IP "\fBNDBUF_RORB\fR"
+Buffer is read-only.
+
+.IP "\fBNDBUF_MOLS\fR"
+Zero-copy buffer.
+
+
+.SH BEHAVIOR AND USAGE NOTES
+
+    Flags are implementation-defined bitmasks; use only the constants defined by libndbuf.
+    Changing flags can affect memory ownership and lifetime semantics (for example, toggling zero-copy/copyless may change whether returned pointers reference internal storage or newly allocated memory). Ensure callers understand implications before changing flags on a buffer containing live data.
+    These functions do not allocate memory themselves. However, changing flags that affect ownership semantics may influence subsequent operations that allocate or free memory.
+    There is no return value; error conditions (if any) are reported via ndbuf_t state or other library diagnostics. Passing a NULL pointer yields undefined behavior.
+
+.SH THREAD SAFETY
+Concurrent modification of flags on the same ndbuf_t without external synchronization is unsafe. Use appropriate locking when multiple threads may read or modify flags.
+
+.SH EXAMPLES
+.nf
+/* Set buffer to copyless (zero-copy) and burn mode */
+ndbuf_setflags(buf, NDBUF_MOLS | NDBUF_BURN);
+
+/* Clear all flags */
+ndbuf_flagsreset(buf);
+
+/* Exchange flags - set read-only */
+ndbuf_exflags(buf, NDBUF_RORB);
+.nf
+
+.SH SEE ALSO
+.BR ndbuf_new(3) ,
+.BR ndbuf_free_item(3) ,
+.BR ndbuf_escan(3) ,
+.BR ndbuf_print(3)
+
+.SH COPYRIGHT
+This software is licensed under the GNU Lesser General Public License version 2.1 or later. See the COPYING file in the project repository for full license text.
+
+.PP
+(c) Authors of libndbuf 2017-2018 (http://vapaa.xyz)
+
+.SH AUTHOR
+Alexander Vdolainen <alex@vapaa.xyz>