nv.9: Add a new subsection documenting kernel-specific behavior

Reviewed by:	emaste
Sponsored by:	Chelsio Communications
Differential Revision:	https://reviews.freebsd.org/D48257

This commit is contained in:

John Baldwin

2025-01-03 10:51:51 -05:00

parent ae1cc4182b

commit ecb5fe3c5e

1 changed files with 31 additions and 1 deletions

									
										share/man/man9/nv.9
									
		+31
		-1
	
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				@@ -859,7 +859,7 @@ If no element named

				.Fa name

				with the appropriate type exists, the program aborts.

				The nvlist must not be in the error state.

				.Sh NOTES

				.Ss Notes

				The

				.Fn nvlist_pack

				and

				@@ -873,6 +873,36 @@ The

				and

				.Fn nvlist_xfer

				functions can transfer nvlists between hosts with different endianness.

				.Ss Kernel Considerations

				The

				.Nm nv ,

				.Nm cnv ,

				and

				.Nm dnv

				APIs can be used in the kernel with the following differences:

				.Bl -bullet

				.It

				File descriptor and file descriptor array value types are not supported.

				.It

				.Fn nvlist_recv ,

				.Fn nvlist_send ,

				and

				.Fn nvlist_xfer

				are not supported.

				.It

				All memory allocations use the

				.Dv M_NVLIST

				memory type with

				.Xr malloc 9

				and

				.Xr free 9 .

				As a result, any allocated buffers moved into an nvlist must be allocated with

				.Dv M_NVLIST ,

				and buffers returned by functions such as

				.Fn nvlist_pack

				must be freed with

				.Dv M_NVLIST .

				.El

				.Sh EXAMPLES

				The following example demonstrates how to prepare an nvlist and send it over a

				.Xr unix 4