Firebird 2.1 FB_SLEEP UDF

udf_fb_sleep.c

/* FB_SLEEP() UDF - pause an FB thread for a number of seconds       */
/* Mike Pomraning 2011 for FB 2.1; this code is in the Public Domain */

#include <sys/select.h>

/*
DECLARE EXTERNAL FUNCTION fb_sleep
        DOUBLE PRECISION
        RETURNS INTEGER BY VALUE
        ENTRY_POINT 'UDF_fb_sleep' MODULE_NAME 'udf_fb_sleep';
 */ 

int UDF_fb_sleep(double *d)
{   
    struct timeval tv;

    tv.tv_sec  = (time_t)*d;
    tv.tv_usec = ((*d - (double)tv.tv_sec) * 1000000.0);

    select(0, NULL, NULL, NULL, &tv);

    return 0;
}