#include    <sys/types.h>
#include    <sys/socket.h>

#include    <stdio.h>
#include    <stdlib.h>
#include    <dlfcn.h>
#include    <paths.h>
#include    <err.h>

#define PRNT_OPER(f)	printf("\t" #f ": %p <%s>\n",   \
	    (void *)fp->##f,	    \
	    _symdesc((void *)(fp->##f)))

#define SYMDESC_FMT "%s (%s)"
static const char *
_symdesc(void *a)
{
    Dl_info dli;
    char    *s;

    if (!dladdr(a, &dli))
	return dlerror();
    if (!(s = malloc(sizeof(SYMDESC_FMT) +
		    strlen(dli.dli_fname) +
		    strlen(dli.dli_sname))))
	err(1, "Cannot allocate memory");
    sprintf(s, SYMDESC_FMT, dli.dli_sname, dli.dli_fname);
    return s;
}

int
main(int ac, char *av[])
{
    struct
    {
	enum {F, P, S}	type;
	char		*desc;
    }		    tl[] = {{F, "file"}, {P, "pipe"}, {S, "socket"}};
    register int    t;

    for (t = 0; t < (sizeof(tl) / sizeof(tl[0])); ++t)
    {
	FILE	*fp = NULL; /* XXX */

	switch (tl[t].type)
	{
	    case F:
		if (!(fp = fopen("/dev/null", "r")))	    /* XXX: Use paths.h */
		    err(1, "Cannot open %s", "/dev/null");
		break;
	    case P:
		if (!(fp = popen("cat", "w")))
		    err(1, "Cannot open pipe to %s", "cat");
		break;
	    case S:
		if (!(fp = (fdopen(socket(PF_LOCAL, SOCK_STREAM, 0),
				    "rw"))))
		    err(1, "Cannot create socket");
		break;
	}
	printf("%s:\n", tl[t].desc);
	printf("\tcookie: %p\n", fp->_cookie);
	PRNT_OPER(_close);
	PRNT_OPER(_read);
	PRNT_OPER(_seek);
	PRNT_OPER(_write);
    }
    return 0;
}