# HiLog\_Lite Development
## Overview
HiLog\_Lite is the HiLog framework for Mini-System Devices \(reference memory ≥ 128 KiB\) and Small-System Devices \(reference memory ≥ 1 MiB\). It implements functions such as log printing, log output, and flow control.
## Available APIs
HiLog\_lite provides the following C APIs:
```
HILOG_DEBUG(mod, fmt, ...)
HILOG_INFO/HILOG_WARN/HILOG_ERROR/HILOG_FATAL
```
**Table 1** Parameters of C APIs
Parameter
Mandatory?
Data Type
Description
mod
Yes
uint8
Indicates the module or service ID.
IDs are planned and assigned in a unified manner. A maximum of 64 IDs are supported. Third-party applications use HILOG_MODULE_APP as their module ID.
fmt
Yes
char *
Indicates the format specifier for output.
A maximum of six variable parameters are supported. %s is not supported.
The maximum length of a formatted log record is 128 bytes. If the maximum length is exceeded, the log cannot be printed.
Variable parameters
No
int32
Only numeric types are supported. A maximum of six variable parameters are allowed.
## How to Develop
The following provides an example of how the Samgr\_Lite module uses the HiLog\_Lite framework.
1. Add the module ID, and define **HILOG\_MODULE\_SAMGR** in the **HiLogModuleType** structure in **base/hiviewdfx/hilog\_lite/interfaces/native/kits/hilog\_lite/hiview\_log.h**.
```
typedef enum {
...
HILOG_MODULE_SAMGR,
...
} HiLogModuleType;
```
2. Register the module. Specifically, add the registration code to the **HiLogInit** function in **base/hiviewdfx/hilog\_lite/frameworks/mini/hiview\_log.c**.
```
HiLogRegisterModule(HILOG_MODULE_SAMGR, "SAMGR");
```
3. Add the header file dependencies to the **foundation/systemabilitymgr/samgr\_lite/samgr/BUILD.gn** file.
```
include_dirs = [
"//base/hiviewdfx/hilog_lite/interfaces/native/kits/hilog_lite",
]
```
4. Reference the header file in the **foundation/systemabilitymgr/samgr\_lite/samgr/source/message.c** file and call the related APIs.
```
#include
uint32 *SAMGR_SendSharedRequest(const Identity *identity, const Request *request, uint32 *token, Handler handler)
{
...
if (err != EC_SUCCESS) {
HILOG_ERROR(HILOG_MODULE_SAMGR, "SharedSend [%p] failed(%d)!", identity->queueId, err);
(void)FreeReference(&exchange);
}
...
}
```