NAME

       nbdkit_debug, nbdkit_vdebug - print debugging messages for nbdkit

SYNOPSIS

        #include <nbdkit-plugin.h>

        void nbdkit_debug (const char *fs, ...);
        void nbdkit_vdebug (const char *fs, va_list args);

DESCRIPTION

       Use "nbdkit_debug" or "nbdkit_vdebug" to print debug messages from your plugin or filter.

       These functions send the debug message to stderr.  Debug messages are only emitted when the server is in
       verbose mode (nbdkit -v option)

       "nbdkit_debug" works like printf(3).  "nbdkit_vdebug" works like vprintf(3).

       For convenience both these functions preserve the value of "errno", and also support the glibc extension
       of a single %m in a format string expanding to strerror(errno), even on platforms that don't support that
       natively.

LANGUAGE BINDINGS

       In nbdkit-golang-plugin(3):

        import "libguestfs.org/nbdkit"
        nbdkit.Debug(msg)

       In nbdkit-ocaml-plugin(3):

        NBDKit.debug : ('a, unit, string, unit) format4 -> 'a

       In nbdkit-perl-plugin(3):

        Nbdkit::debug ($msg);

       In nbdkit-python-plugin(3):

        import nbdkit
        nbdkit.debug(str)

       In nbdkit-rust-plugin(3):

        use nbdkit::*;
        debug!(fs, ...);

HISTORY

       "nbdkit_debug" was present in nbdkit 0.1.0.

SEE ALSO

       nbdkit(1), nbdkit_error(3), nbdkit-plugin(3), nbdkit-filter(3).

AUTHORS

       Richard W.M. Jones

COPYRIGHT

       Copyright Red Hat

LICENSE

       Redistribution and use in source and binary forms, with or without modification, are permitted provided
       that the following conditions are met:

       •   Redistributions  of  source  code must retain the above copyright notice, this list of conditions and
           the following disclaimer.

       •   Redistributions in binary form must reproduce the above copyright notice, this list of conditions and
           the following disclaimer in the documentation and/or other materials provided with the distribution.

       •   Neither the name of Red Hat nor the names of its contributors may  be  used  to  endorse  or  promote
           products derived from this software without specific prior written permission.

       THIS  SOFTWARE  IS  PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
       INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND  FITNESS  FOR  A  PARTICULAR
       PURPOSE  ARE  DISCLAIMED.  IN  NO EVENT SHALL RED HAT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
       INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,  PROCUREMENT  OF
       SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
       ON  ANY  THEORY  OF  LIABILITY,  WHETHER  IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
       OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
       DAMAGE.

nbdkit-1.42.2                                      2025-04-02                                    nbdkit_debug(3)