VND_ERRNO(3VND)VND_ERRNO(3VND)NAME
vnd_errno, vnd_syserrno, vnd_strerror, vnd_strsyserror - obtain and
translate vnd errors
SYNOPSIS
cc [ flag... ] file... -lvnd [ library... ]
#include <libvnd.h>
uint32_t vnd_errno(vnd_handle_t *vhp);
const char *vnd_strerror(vnd_errno_t err);
int vnd_syserrno(vnd_handle_t *vhp);
const char *vnd_strsyserror(int syserr);
DESCRIPTION
The libvnd(3LIB) library supports a complementary array of errors that
give more specific error information than the traditional set of system
errors available via errno(3C). When an error occurs, consumers should
call the vnd_errno function first and check its value. If the value of
the vnd_errno_t is VND_E_SYS, then the system errno should be checked.
If the vnd_errno_t is not VND_E_SYS, then the contents of the system
errno returned from vnd_syserrno are undefined. Both the vnd and system
errors are only valid for a given handle after a libvnd library func‐
tion returned an error and before another libvnd library function is
called on the same handle. The act of making an additional function
call with the same vnd_handle_t invalidates any prior vnd or system
error numbers. For the full list of valid vnd errors see libvnd(3LIB).
For the full list of valid system errors, see Intro(2).
The vnd_errno and vnd_syserrno functions retrieve the most recent vnd
and syserr error number respectively from a vnd handle vhp.
The vnd_strerror function translates a vnd_errno_t err to a correspond‐
ing string and returns a pointer to that constant string.
The vnd_syserrno function is analogous to the vnd_strerror function,
except that it translates a system error back to a string.
RETURN VALUES
The vnd_errno function returns a vnd_errno_t which contains the vnd
error information.
The vnd_syserror function returns an integer which contains the system
error information. These values are the same as those returned by
errno(3C).
The vnd_strerror function returns a pointer to a constant string. If
the error passed in is unknown, the string "unknown error" is returned.
The vnd_strsyserror function returns a pointer to the translated con‐
stant string. If an unknown error number is passed, it returns the
string "Unknown error". If an error occurs, it returns a NULL pointer.
EXAMPLES
Example 1 Obtaining errors from a vnd_handle_t
The following sample C function, which can be incorporated into a
larger program, shows how to obtain the vnd and system errors from a
vnd_handle_t after a vnd interface on a handle failed.
#include <libvnd.h>
static void
print_errnos(vnd_handle_t *vhp)
{
vnd_errno_t vnderr;
int syserr;
vnderr = vnd_errno(vhp);
syserr = vnd_syserrno(vhp);
(void) printf("vnd err: %d, sys err: %d0,
vnderr, syserr);
}
Example 2 A perror-like function
The following sample C function which can be incorporated into a larger
program shows how to write a perror-like function to print out error
messages for a vnd device.
#include <libvnd.h>
static void
sample_perror(const char *msg, vnd_error_t vnderr, int syserr)
{
(void) fprintf(stderr, "%s: %s", msg,
vnderr != VND_E_SYS ? vnd_strerror(vnderr) :
vnd_strsyserror(syserr));
}
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌───────────────┬─────────────────┐
│ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├───────────────┼─────────────────┤
│Stability │ Committed │
├───────────────┼─────────────────┤
│MT-Level │ See below │
└───────────────┴─────────────────┘
The MT-Level of the functions vnd_strerror and vnd_strsyserror is MT-
Safe. See "THREADING" in libvnd(3LIB) for a discussion of the MT-Level
of vnd_errno and vnd_syserrno.
SEE ALSOIntro(2), errno(3C), libvnd(3LIB), attributes(5)
Feb 21, 2014 VND_ERRNO(3VND)
