自学教程：C++ virLastErrorObject函数代码示例

/** * virDispatchError: * @conn: pointer to the hypervisor connection * * Internal helper to do final stage of error * reporting in public APIs. * *  - Copy the global error to per-connection error if needed *  - Set a generic error message if none is already set *  - Invoke the error callback functions */voidvirDispatchError(virConnectPtr conn){    virErrorPtr err = virLastErrorObject();    virErrorFunc handler = virErrorHandler;    void *userData = virUserData;    /* Can only happen on OOM.  */    if (!err)        return;    /* Set a generic error message if none is already set */    if (err->code == VIR_ERR_OK)        virErrorGenericFailure(err);    /* Copy the global error to per-connection error if needed */    if (conn) {        virMutexLock(&conn->lock);        virCopyError(err, &conn->err);        if (conn->handler != NULL) {            handler = conn->handler;            userData = conn->userData;        }        virMutexUnlock(&conn->lock);    }    /* Invoke the error callback functions */    if (handler != NULL) {        (handler)(userData, err);    } else {        virDefaultErrorFunc(err);    }}

/** * virResetLastError: * * Reset the last error caught at the library level. * * The error object is kept in thread local storage, so separate * threads can safely access this concurrently, only resetting * their own error object. */voidvirResetLastError(void){    virErrorPtr err = virLastErrorObject();    if (err)        virResetError(err);}

/** * virGetLastError: * * Provide a pointer to the last error caught at the library level * * The error object is kept in thread local storage, so separate * threads can safely access this concurrently. * * Returns a pointer to the last error or NULL if none occurred. */virErrorPtrvirGetLastError(void){    virErrorPtr err = virLastErrorObject();    if (!err || err->code == VIR_ERR_OK)        return NULL;    return err;}

/** * virGetLastErrorDomain: * * Get the most recent error domain (enum virErrorDomain). * * Returns a numerical value of the most recent error's origin, or VIR_FROM_NONE * if none is set. */intvirGetLastErrorDomain(void){    virErrorPtr err = virLastErrorObject();    if (!err)        return VIR_FROM_NONE;    return err->domain;}

/** * virGetLastErrorCode: * * Get the most recent error code (enum virErrorNumber). * * Returns the most recent error code, or VIR_ERR_OK if none is set. */intvirGetLastErrorCode(void){    virErrorPtr err = virLastErrorObject();    if (!err)        return VIR_ERR_OK;    return err->code;}

/** * virGetLastErrorMessage: * * Get the most recent error message * * Returns the most recent error message string in this * thread, or a generic message if none is set */const char *virGetLastErrorMessage(void){    virErrorPtr err = virLastErrorObject();    if (!err || err->code == VIR_ERR_OK)        return _("no error");    if (err->message == NULL)        return _("unknown error");    return err->message;}

/** * virCopyLastError: * @to: target to receive the copy * * Copy the content of the last error caught at the library level * * The error object is kept in thread local storage, so separate * threads can safely access this concurrently. * * One will need to free the result with virResetError() * * Returns 0 if no error was found and the error code otherwise and -1 in case *         of parameter error. */intvirCopyLastError(virErrorPtr to){    virErrorPtr err = virLastErrorObject();    /* We can't guarantee caller has initialized it to zero */    memset(to, 0, sizeof(*to));    if (err)        virCopyError(err, to);    else        virResetError(to);    return to->code;}

/** * virSetError: * @newerr: previously saved error object * * Set the current error from a previously saved error object * * Can be used to re-set an old error, which may have been squashed by * other functions (like cleanup routines). * * Returns 0 on success, -1 on failure.  Leaves errno unchanged. */intvirSetError(virErrorPtr newerr){    virErrorPtr err;    int saved_errno = errno;    int ret = -1;    err = virLastErrorObject();    if (!err)        goto cleanup;    virResetError(err);    ret = virCopyError(newerr, err);cleanup:    errno = saved_errno;    return ret;}

/** * virCopyLastError: * @to: target to receive the copy * * Copy the content of the last error caught at the library level * * The error object is kept in thread local storage, so separate * threads can safely access this concurrently. * * One will need to free the result with virResetError() * * Returns error code or -1 in case of parameter error. */intvirCopyLastError(virErrorPtr to){    virErrorPtr err = virLastErrorObject();    if (!to)        return -1;    /* We can't guarantee caller has initialized it to zero */    memset(to, 0, sizeof(*to));    if (err) {        virCopyError(err, to);    } else {        virResetError(to);        to->code = VIR_ERR_NO_MEMORY;        to->domain = VIR_FROM_NONE;        to->level = VIR_ERR_ERROR;    }    return to->code;}

                  const char *str3,                  int int1,                  int int2,                  const char *fmt, ...){    int save_errno = errno;    virErrorPtr to;    char *str;    int priority;    /*     * All errors are recorded in thread local storage     * For compatibility, public API calls will copy them     * to the per-connection error object when necessary     */    to = virLastErrorObject();    if (!to) {        errno = save_errno;        return; /* Hit OOM allocating thread error object, sod all we can do now */    }    virResetError(to);    if (code == VIR_ERR_OK) {        errno = save_errno;        return;    }    /*     * formats the message; drop message on OOM situations     */