# lv_os.h (/api/osal/lv_os_h)
Functions [#functions]
lv_lock [#lv_lock]
Lock LVGL's general mutex. LVGL is not thread safe, so a mutex is used to avoid executing multiple LVGL functions at the same time from different threads. It shall be called when calling LVGL functions from threads different than lv\_timer\_handler's thread. It doesn't need to be called in LVGL events because they are called from . It is called internally in .
```c title=" " lineNumbers=1
void lv_lock(void)
```
lv_lock_isr [#lv_lock_isr]
Same as but can be called from an interrupt.
```c title=" " lineNumbers=1
lv_result_t lv_lock_isr(void)
```
**Returns:** — LV\_RESULT\_OK: success; LV\_RESULT\_INVALID: failure
lv_unlock [#lv_unlock]
The pair of and . It unlocks LVGL general mutex. It is called internally in .
```c title=" " lineNumbers=1
void lv_unlock(void)
```
lv_sleep_ms [#lv_sleep_ms]
Sleeps the current thread by an amount of milliseconds.
```c title=" " lineNumbers=1
void lv_sleep_ms(uint32_t ms)
```
Parameters
| Name | Type | Description |
| ---- | --------------------------- | --------------------------------------------------- |
| `ms` | | amount of milliseconds to sleep the current thread. |
Dependencies [#dependencies]