% limb manual
% obuffer_level(3)
% limb 0.1.0
% 2023-07-24

# NAME

obuffer\_level, obuffer\_setlevel - get/set the level of an output buffer

# SYNOPSIS

    #include <limb/obuffer.h>

```pre hl
u8 obuffer_level(obuffer *<em>obuf</em>)
void obuffer_setlevel(obuffer *<em>obuf</em>, u8 <em>level</em>)
```

# DESCRIPTION

The `obuffer_level`() macro returns the current level of the output buffer
pointed by `obuf`.

The `obuffer_setlevel`() macro will set the level of the output buffer pointed
by `obuf` to `level`.

The following constants are defined as common levels, ordered from lower to
higher :

- *OLVL_SILENT*
: Meant to be silent, i.e. disabled. (There should never be data sent with such
: a level.)

- *OLVL_QUIET*
: For the most minimum/required messages only.

- *OLVL_NORMAL*
: For regular output.

- *OLVL_VERBOSE*
: For additional/verbose output.

- *OLVL_DEBUG*
: Meant for debugging output only. See the [dbg](3) macro to automatically
: prefix messages with file & function name as well as line number.

- *OLVL_MAXIMUM*
: If you need extra/verbose debugging messages.

As you must have guessed, the idea is simply to assign a level to different
output, which can then be filtered at runtime by changing the level of the
output buffer.

Thus, all functions that write data to an output buffer actually check first
that the output buffer's level is at least that associated with the data. Only
then will data be sent/written to the underlying buffer.

If the buffer has a lower level, then nothing is done.

Note that this check is actually performed for /every/ output buffer in the
chain, each buffer having its own level to determine whether or not to get
written to.

For more about chains of output buffers, refer to [obuffer_attach](3).

# SEE ALSO

[output.h](0)