1# sem<a name="EN-US_TOPIC_0000001134006254"></a> 2 3- [Command Function](#section366714216619) 4- [Syntax](#section8833164614615) 5- [Parameters](#section12809111019453) 6- [Usage](#section15935131220717) 7- [Example](#section79281818476) 8- [Output](#section1975118519456) 9 10## Command Function<a name="section366714216619"></a> 11 12This command is used to query information about kernel semaphores. 13 14## Syntax<a name="section8833164614615"></a> 15 16sem \[_ID__ / fulldata_\] 17 18## Parameters<a name="section12809111019453"></a> 19 20**Table 1** Parameter description 21 22<a name="table438mcpsimp"></a> 23<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>Parameter</p> 24</th> 25<th class="cellrowborder" valign="top" width="52%" id="mcps1.2.4.1.2"><p id="p448mcpsimp"><a name="p448mcpsimp"></a><a name="p448mcpsimp"></a>Parameters</p> 26</th> 27<th class="cellrowborder" valign="top" width="27%" id="mcps1.2.4.1.3"><p id="p450mcpsimp"><a name="p450mcpsimp"></a><a name="p450mcpsimp"></a>Value Range</p> 28</th> 29</tr> 30</thead> 31<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> 32</td> 33<td class="cellrowborder" valign="top" width="52%" headers="mcps1.2.4.1.2 "><p id="p455mcpsimp"><a name="p455mcpsimp"></a><a name="p455mcpsimp"></a>Specifies the semaphore ID.</p> 34</td> 35<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> 36</td> 37</tr> 38<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> 39</td> 40<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="b189454249533849"><a name="b189454249533849"></a><a name="b189454249533849"></a>SemID</strong>, <strong id="b162724654333849"><a name="b162724654333849"></a><a name="b162724654333849"></a>Count</strong>, <strong id="b111325307233849"><a name="b111325307233849"></a><a name="b111325307233849"></a>OriginalCount</strong>, <strong id="b182850346833849"><a name="b182850346833849"></a><a name="b182850346833849"></a>Creater(TaskEntry)</strong>, and <strong id="b213750533633849"><a name="b213750533633849"></a><a name="b213750533633849"></a>LastAccessTime</strong>.</p> 41</td> 42<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> 43</td> 44</tr> 45</tbody> 46</table> 47 48## Usage<a name="section15935131220717"></a> 49 50- If the parameters are not specified, this command displays the number of used semaphores and the total number of semaphores. 51- If the **ID** parameter is specified, semaphores of the specified ID are displayed. 52- The **fulldata** parameter depends on **LOSCFG\_DEBUG\_SEMAPHORE**. Before using this parameter, select **Enable Semaphore Debugging** on **menuconfig**. 53 54 Debug ---\> Enable a Debug Version ---\> Enable Debug LiteOS Kernel Resource ---\> Enable Semaphore Debugging 55 56 57## Example<a name="section79281818476"></a> 58 59Run **sem fulldata**. 60 61## Output<a name="section1975118519456"></a> 62 63**Figure 1** Querying information about all semaphores in use<a name="fig18750181620222"></a> 64 65 66**Table 2** Output 67 68<a name="table487mcpsimp"></a> 69<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> 70</th> 71<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> 72</th> 73</tr> 74</thead> 75<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> 76</td> 77<td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.2 "><p id="p501mcpsimp"><a name="p501mcpsimp"></a><a name="p501mcpsimp"></a>Semaphore ID</p> 78</td> 79</tr> 80<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> 81</td> 82<td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.2 "><p id="p506mcpsimp"><a name="p506mcpsimp"></a><a name="p506mcpsimp"></a>Number of used semaphores</p> 83</td> 84</tr> 85</tbody> 86</table> 87 88> **NOTE:** 89>The **ID** value can be in decimal or hexadecimal format. 90>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 parameter is incorrect. 91 92
