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sem.md 5.66 KB

# sem<a name="EN-US_TOPIC_0000001052810290"></a>

-   [Command Function](#section366714216619)
-   [Syntax](#section8833164614615)
-   [Parameter Description](#section12809111019453)
-   [Usage](#section15935131220717)
-   [Example](#section79281818476)
-   [Output](#section1975118519456)

## Command Function<a name="section366714216619"></a>

This command is used to query information about kernel semaphores.

## Syntax<a name="section8833164614615"></a>

sem \[_ID__ / fulldata_\]

## Parameter Description<a name="section12809111019453"></a>

**Table  1**  Parameters

<a name="table438mcpsimp"></a>
<table><thead align="left"><tr id="row444mcpsimp"><th class="cellrowborder" valign="top" width="21%" id="mcps1.2.4.1.1"><p id="p446mcpsimp"><a name="p446mcpsimp"></a><a name="p446mcpsimp"></a><strong id="b1111222772019"><a name="b1111222772019"></a><a name="b1111222772019"></a>Parameter</strong></p>
</th>
<th class="cellrowborder" valign="top" width="52%" id="mcps1.2.4.1.2"><p id="p448mcpsimp"><a name="p448mcpsimp"></a><a name="p448mcpsimp"></a><strong id="b84871307209"><a name="b84871307209"></a><a name="b84871307209"></a>Description</strong></p>
</th>
<th class="cellrowborder" valign="top" width="27%" id="mcps1.2.4.1.3"><p id="p450mcpsimp"><a name="p450mcpsimp"></a><a name="p450mcpsimp"></a><strong id="b101742225281"><a name="b101742225281"></a><a name="b101742225281"></a>Value Range</strong></p>
</th>
</tr>
</thead>
<tbody><tr id="row451mcpsimp"><td class="cellrowborder" valign="top" width="21%" headers="mcps1.2.4.1.1 "><p id="p453mcpsimp"><a name="p453mcpsimp"></a><a name="p453mcpsimp"></a>ID</p>
</td>
<td class="cellrowborder" valign="top" width="52%" headers="mcps1.2.4.1.2 "><p id="p455mcpsimp"><a name="p455mcpsimp"></a><a name="p455mcpsimp"></a>Indicates the semaphore ID.</p>
</td>
<td class="cellrowborder" valign="top" width="27%" headers="mcps1.2.4.1.3 "><p id="p457mcpsimp"><a name="p457mcpsimp"></a><a name="p457mcpsimp"></a>[0, 0xFFFFFFFF]</p>
</td>
</tr>
<tr id="row458mcpsimp"><td class="cellrowborder" valign="top" width="21%" headers="mcps1.2.4.1.1 "><p id="p460mcpsimp"><a name="p460mcpsimp"></a><a name="p460mcpsimp"></a>fulldata</p>
</td>
<td class="cellrowborder" valign="top" width="52%" headers="mcps1.2.4.1.2 "><p id="p462mcpsimp"><a name="p462mcpsimp"></a><a name="p462mcpsimp"></a>Queries information about all the semaphores in use. The information to be printed includes <strong id="b20538161115251"><a name="b20538161115251"></a><a name="b20538161115251"></a>SemID</strong>, <strong id="b18465101411257"><a name="b18465101411257"></a><a name="b18465101411257"></a>Count</strong>, <strong id="b11825131802514"><a name="b11825131802514"></a><a name="b11825131802514"></a>OriginalCount</strong>, <strong id="b626012213257"><a name="b626012213257"></a><a name="b626012213257"></a>Creater(TaskEntry)</strong>, and <strong id="b1176182715258"><a name="b1176182715258"></a><a name="b1176182715258"></a>LastAccessTime</strong>.</p>
</td>
<td class="cellrowborder" valign="top" width="27%" headers="mcps1.2.4.1.3 "><p id="entry464mcpsimpp0"><a name="entry464mcpsimpp0"></a><a name="entry464mcpsimpp0"></a>N/A</p>
</td>
</tr>
</tbody>
</table>

## Usage<a name="section15935131220717"></a>

-   If the parameters are not specified, this command displays the number of used semaphores and the total number of semaphores.
-   If the  **ID**  parameter is specified, semaphores of the specified ID are displayed.
-   The  **fulldata**  parameter depends on  **LOSCFG\_DEBUG\_SEMAPHORE**. Before specifying the  **fulldata**  parameter, enable the  **Enable Semaphore Debugging**  configuration item using  **menuconfig**.

Debug  ---\> Enable a Debug Version ---\> Enable Debug LiteOS Kernel Resource ---\> Enable Semaphore Debugging

## Example<a name="section79281818476"></a>

Example 1: Enter  **sem fulldata**.

## Output<a name="section1975118519456"></a>

**Figure  1**  Querying information about all semaphores in use<a name="fig18750181620222"></a>  
![](figures/querying-information-about-all-semaphores-in-use.png "querying-information-about-all-semaphores-in-use")

**Table  2**  Output description

<a name="table487mcpsimp"></a>
<table><thead align="left"><tr id="row492mcpsimp"><th class="cellrowborder" valign="top" width="50%" id="mcps1.2.3.1.1"><p id="p494mcpsimp"><a name="p494mcpsimp"></a><a name="p494mcpsimp"></a>Parameter</p>
</th>
<th class="cellrowborder" valign="top" width="50%" id="mcps1.2.3.1.2"><p id="p496mcpsimp"><a name="p496mcpsimp"></a><a name="p496mcpsimp"></a>Description</p>
</th>
</tr>
</thead>
<tbody><tr id="row497mcpsimp"><td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.1 "><p id="p499mcpsimp"><a name="p499mcpsimp"></a><a name="p499mcpsimp"></a>SemID</p>
</td>
<td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.2 "><p id="p501mcpsimp"><a name="p501mcpsimp"></a><a name="p501mcpsimp"></a>Indicates the semaphore ID.</p>
</td>
</tr>
<tr id="row502mcpsimp"><td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.1 "><p id="p504mcpsimp"><a name="p504mcpsimp"></a><a name="p504mcpsimp"></a>Count</p>
</td>
<td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.2 "><p id="p506mcpsimp"><a name="p506mcpsimp"></a><a name="p506mcpsimp"></a>Indicates the number of used semaphores.</p>
</td>
</tr>
</tbody>
</table>

>![](public_sys-resources/icon-note.gif) **NOTE:** 
>-   The  **ID**  value can be in decimal or hexadecimal format.
>-   When the  **ID**  value is within the range of \[0, 1023\], semaphore information of the specified ID is displayed. If the semaphore ID is not used, a message is displayed to inform you of this case. For other values, a message is displayed indicating that the input parameter is incorrect.

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提交于 2021-03-12 17:59 . !197 Docs Update version 1.0.1

sem

Command Function
Syntax
Parameter Description
Usage
Example
Output

Command Function

This command is used to query information about kernel semaphores.

Syntax

sem [ID_ / fulldata_]

Parameter Description

Table 1 Parameters

Parameter	Description	Value Range
ID	Indicates the semaphore ID.	[0, 0xFFFFFFFF]
fulldata	Queries information about all the semaphores in use. The information to be printed includes SemID, Count, OriginalCount, Creater(TaskEntry), and LastAccessTime.	N/A

Usage

If the parameters are not specified, this command displays the number of used semaphores and the total number of semaphores.
If the ID parameter is specified, semaphores of the specified ID are displayed.
The fulldata parameter depends on LOSCFG_DEBUG_SEMAPHORE. Before specifying the fulldata parameter, enable the Enable Semaphore Debugging configuration item using menuconfig.

Debug ---> Enable a Debug Version ---> Enable Debug LiteOS Kernel Resource ---> Enable Semaphore Debugging

Example

Example 1: Enter sem fulldata.

Output

Figure 1 Querying information about all semaphores in use

Table 2 Output description

Parameter	Description
SemID	Indicates the semaphore ID.
Count	Indicates the number of used semaphores.

NOTE:

The ID value can be in decimal or hexadecimal format.

When the ID value is within the range of [0, 1023], semaphore information of the specified ID is displayed. If the semaphore ID is not used, a message is displayed to inform you of this case. For other values, a message is displayed indicating that the input parameter is incorrect.

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