+ /** Sound pressure level is A-weighted in the frequency domain,
+ * according to IEC 61672:2003. */
+ SR_MQFLAG_SPL_FREQ_WEIGHT_A = 0x200,
+ /** Sound pressure level is C-weighted in the frequency domain,
+ * according to IEC 61672:2003. */
+ SR_MQFLAG_SPL_FREQ_WEIGHT_C = 0x400,
+ /** Sound pressure level is Z-weighted (i.e. not at all) in the
+ * frequency domain, according to IEC 61672:2003. */
+ SR_MQFLAG_SPL_FREQ_WEIGHT_Z = 0x800,
+ /** Sound pressure level is not weighted in the frequency domain,
+ * albeit without standards-defined low and high frequency limits. */
+ SR_MQFLAG_SPL_FREQ_WEIGHT_FLAT = 0x1000,
+ /** Sound pressure level measurement is S-weighted (1s) in the
+ * time domain. */
+ SR_MQFLAG_SPL_TIME_WEIGHT_S = 0x2000,
+ /** Sound pressure level measurement is F-weighted (125ms) in the
+ * time domain. */
+ SR_MQFLAG_SPL_TIME_WEIGHT_F = 0x4000,
+ /** Sound pressure level is time-averaged (LAT), also known as
+ * Equivalent Continuous A-weighted Sound Level (LEQ). */
+ SR_MQFLAG_SPL_LAT = 0x8000,
+ /** Sound pressure level represented as a percentage of measurements
+ * that were over a preset alarm level. */
+ SR_MQFLAG_SPL_PCT_OVER_ALARM = 0x10000,
+ /** Time is duration (as opposed to epoch, ...). */
+ SR_MQFLAG_DURATION = 0x20000,
+ /** Device is in "avg" mode, averaging upon each new value. */
+ SR_MQFLAG_AVG = 0x40000,
+};
+
+/**
+ * @struct sr_context
+ * Opaque structure representing a libsigrok context.
+ *
+ * None of the fields of this structure are meant to be accessed directly.
+ *
+ * @see sr_init(), sr_exit().
+ */
+struct sr_context;