plucky (3) nbdkit_strndup_intern.3.gz

Provided by: nbdkit-plugin-dev_1.42.0-1ubuntu1_amd64 bug

NAME
       nbdkit_strdup_intern, nbdkit_strndup_intern, nbdkit_printf_intern, nbdkit_vprintf_intern - create a
       string with limited lifetime for nbdkit


SYNOPSIS
        #include <nbdkit-plugin.h>

        const char *nbdkit_strdup_intern (const char *str);
        const char *nbdkit_strndup_intern (const char *str, size_t n);
        const char *nbdkit_printf_intern (const char *fmt, ...);
        const char *nbdkit_vprintf_intern (const char *fmt, va_list ap);


DESCRIPTION
       Some callbacks are specified to return "const char *", even when a plugin may not have a suitable
       compile-time constant to return.  Returning dynamically-allocated memory for such a callback would induce
       a memory leak or otherwise complicate the plugin to perform additional bookkeeping.  For these cases,
       nbdkit provides several convenience functions for creating a copy of a string for better lifetime
       management.

   nbdkit_strdup_intern
   nbdkit_strndup_intern
       Returns a copy of "str", possibly limited to a maximum of "n" bytes.  After calling this, the plugin may
       free "str" and use this copy in its place.

       If the copy is created outside the scope of a connection (such as during ".load" or ".config"), the
       lifetime of the copy will last at least through ".unload".

       If the copy is created after a client has triggered a connection (such as during ".preconnect" or
       ".open"), the lifetime will last at least through ".close", but the copy is not safe to share with other
       connections.

   "nbdkit_printf_intern"
   "nbdkit_vprintf_intern"
       Return a string created from a format template, with a lifetime longer than the current connection.
       These are shorthand for passing "fmt" to asprintf(3) on a temporary string, then passing that result to
       "nbdkit_strdup_intern".


RETURN VALUE
       These functions return a string.  This returned string must not be freed by the caller.  It will be freed
       by nbdkit.

       If there is an error they call nbdkit_error(3) and return -1.


HISTORY
       The intern functions were added in nbdkit 1.24.


SEE ALSO
       nbdkit(1), nbdkit-plugin(3), nbdkit-filter(3).


AUTHORS
       Eric Blake


       Copyright Red Hat


LICENSE
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       that the following conditions are met:

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           the following disclaimer.

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           products derived from this software without specific prior written permission.

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       INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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