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 either stderr or the system logs depending on
       the current server state and the user-specified nbdkit --log option.  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

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