[docs] use `NULL` in place of `nullptr` (#11435)
diff --git a/include/openthread/backbone_router_ftd.h b/include/openthread/backbone_router_ftd.h
index 64fc716..e275519 100644
--- a/include/openthread/backbone_router_ftd.h
+++ b/include/openthread/backbone_router_ftd.h
@@ -328,7 +328,7 @@
*
* @param[in] aContext The user context pointer.
* @param[in] aEvent The ND Proxy event.
- * @param[in] aDua The Domain Unicast Address of the ND Proxy, or `nullptr` if @p aEvent is
+ * @param[in] aDua The Domain Unicast Address of the ND Proxy, or NULL if @p aEvent is
* `OT_BACKBONE_ROUTER_NDPROXY_CLEARED`.
*/
typedef void (*otBackboneRouterNdProxyCallback)(void *aContext,
@@ -385,7 +385,7 @@
*
* @param[in] aContext The user context pointer.
* @param[in] aEvent The Domain Prefix event.
- * @param[in] aDomainPrefix The new Domain Prefix if added or changed, nullptr otherwise.
+ * @param[in] aDomainPrefix The new Domain Prefix if added or changed, NULL otherwise.
*/
typedef void (*otBackboneRouterDomainPrefixCallback)(void *aContext,
otBackboneRouterDomainPrefixEvent aEvent,
diff --git a/include/openthread/instance.h b/include/openthread/instance.h
index a8cd3b5..5e3c693 100644
--- a/include/openthread/instance.h
+++ b/include/openthread/instance.h
@@ -52,7 +52,7 @@
*
* @note This number versions both OpenThread platform and user APIs.
*/
-#define OPENTHREAD_API_VERSION (499)
+#define OPENTHREAD_API_VERSION (500)
/**
* @addtogroup api-instance
diff --git a/include/openthread/link.h b/include/openthread/link.h
index ccdc2c7..5d41d1d 100644
--- a/include/openthread/link.h
+++ b/include/openthread/link.h
@@ -1102,7 +1102,7 @@
* @param[out] aRegionCode The radio region code. The `aRegionCode >> 8` is first ascii char
* and the `aRegionCode & 0xff` is the second ascii char.
*
- * @retval OT_ERROR_INVALID_ARGS @p aRegionCode is nullptr.
+ * @retval OT_ERROR_INVALID_ARGS @p aRegionCode is NULL.
* @retval OT_ERROR_FAILED Other platform specific errors.
* @retval OT_ERROR_NONE Successfully got region code.
* @retval OT_ERROR_NOT_IMPLEMENTED The feature is not implemented.
diff --git a/include/openthread/nat64.h b/include/openthread/nat64.h
index 1ac9370..c6c6ace 100644
--- a/include/openthread/nat64.h
+++ b/include/openthread/nat64.h
@@ -446,7 +446,7 @@
* truncated but the outputted string is always null-terminated.
*
* @param[in] aAddress A pointer to an IPv4 address (MUST NOT be NULL).
- * @param[out] aBuffer A pointer to a char array to output the string (MUST NOT be `nullptr`).
+ * @param[out] aBuffer A pointer to a char array to output the string (MUST NOT be NULL).
* @param[in] aSize The size of @p aBuffer (in bytes).
*/
void otIp4AddressToString(const otIp4Address *aAddress, char *aBuffer, uint16_t aSize);
@@ -474,7 +474,7 @@
* truncated but the outputted string is always null-terminated.
*
* @param[in] aCidr A pointer to an IPv4 CIDR (MUST NOT be NULL).
- * @param[out] aBuffer A pointer to a char array to output the string (MUST NOT be `nullptr`).
+ * @param[out] aBuffer A pointer to a char array to output the string (MUST NOT be NULL).
* @param[in] aSize The size of @p aBuffer (in bytes).
*/
void otIp4CidrToString(const otIp4Cidr *aCidr, char *aBuffer, uint16_t aSize);
diff --git a/include/openthread/platform/dns.h b/include/openthread/platform/dns.h
index 326fded..e15e843 100644
--- a/include/openthread/platform/dns.h
+++ b/include/openthread/platform/dns.h
@@ -87,11 +87,11 @@
* The transaction will be released, so the platform must not call on the same transaction twice. This function passes
* the ownership of `aResponse` to OpenThread stack.
*
- * Platform can pass a nullptr to close a transaction without a response.
+ * Platform can pass NULL to close a transaction without a response.
*
* @param[in] aInstance The OpenThread instance structure.
* @param[in] aTxn A pointer to the opaque DNS query transaction object.
- * @param[in] aResponse A message buffer of the DNS response payload or `nullptr` to close a transaction without a
+ * @param[in] aResponse A message buffer of the DNS response payload or NULL to close a transaction without a
* response.
*/
extern void otPlatDnsUpstreamQueryDone(otInstance *aInstance, otPlatDnsUpstreamQuery *aTxn, otMessage *aResponse);
diff --git a/include/openthread/platform/multipan.h b/include/openthread/platform/multipan.h
index adece8a..897dcb2 100644
--- a/include/openthread/platform/multipan.h
+++ b/include/openthread/platform/multipan.h
@@ -115,7 +115,7 @@
*
* @param[in] aIid The IID of the interface.
*
- * @retval Instance pointer if aIid is has an instance assigned, nullptr otherwise.
+ * @retval Instance pointer if aIid is has an instance assigned, NULL otherwise.
*/
otInstance *otPlatMultipanIidToInstance(uint8_t aIid);
diff --git a/include/openthread/platform/radio.h b/include/openthread/platform/radio.h
index 8e45fd2..b49be9c 100644
--- a/include/openthread/platform/radio.h
+++ b/include/openthread/platform/radio.h
@@ -1193,7 +1193,7 @@
/**
* Reset CSL receiver in the platform.
*
- * @note Defaults to `otPlatRadioEnableCsl(aInstance,0, Mac::kShortAddrInvalid, nullptr);`
+ * @note Defaults to `otPlatRadioEnableCsl(aInstance,0, Mac::kShortAddrInvalid, NULL);`
*
* @param[in] aInstance The OpenThread instance structure.
*
@@ -1298,7 +1298,7 @@
* @param[in] aInstance The OpenThread instance structure.
* @param[out] aRegionCode The radio region.
*
- * @retval OT_ERROR_INVALID_ARGS @p aRegionCode is nullptr.
+ * @retval OT_ERROR_INVALID_ARGS @p aRegionCode is NULL.
* @retval OT_ERROR_FAILED Other platform specific errors.
* @retval OT_ERROR_NONE Successfully got region code.
* @retval OT_ERROR_NOT_IMPLEMENTED The feature is not implemented.
