nbdkit_strdup_intern, nbdkit_strndup_intern, nbdkit_printf_intern, nbdkit_vprintf_intern - create a string with limited lifetime for nbdkit
#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);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.
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_internnbdkit_vprintf_internReturn 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.
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.
The intern functions were added in nbdkit 1.24.
nbdkit(1), nbdkit-plugin(3), nbdkit-filter(3).
Eric Blake
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