1# sem 2 3## Command Function<a name="section366714216619"></a> 4 5This command is used to query information about kernel semaphores. 6 7## Syntax<a name="section8833164614615"></a> 8 9sem \[_ID__ / fulldata_\] 10 11## Parameters<a name="section12809111019453"></a> 12 13**Table 1** Parameter description 14 15<a name="table438mcpsimp"></a> 16<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> 17</th> 18<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> 19</th> 20<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> 21</th> 22</tr> 23</thead> 24<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> 25</td> 26<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> 27</td> 28<td class="cellrowborder" valign="top" width="27%" headers="mcps1.2.4.1.3 "><p id="p14422125918562"><a name="p14422125918562"></a><a name="p14422125918562"></a>[0, 1023] or [0x0, 0x3FF]</p> 29</td> 30</tr> 31<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> 32</td> 33<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 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> 34</td> 35<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> 36</td> 37</tr> 38</tbody> 39</table> 40 41## Usage<a name="section15935131220717"></a> 42 43- If no parameter is specified, this command displays the semaphore IDs and the number of times that each semaphore is used. 44- If **ID** is specified, the use of the specified semaphore is displayed. 45- The **fulldata** parameter depends on **LOSCFG\_DEBUG\_SEMAPHORE**. Before using this parameter, select **Enable Semaphore Debugging** on **menuconfig**. 46 47 Debug ---\> Enable a Debug Version ---\> Enable Debug LiteOS Kernel Resource ---\> Enable Semaphore Debugging 48 49 50## Example<a name="section79281818476"></a> 51 52- Run **sem**. 53- Configure **LOSCFG\_DEBUG\_SEMAPHORE** and run **sem fulldata**. 54 55## Output<a name="section1975118519456"></a> 56 57Example 1: brief semaphore information 58 59``` 60OHOS # sem 61 SemID Count 62 ---------- ----- 63 0x00000000 1 64 SemID Count 65 ---------- ----- 66 0x00000001 0 67 SemID Count 68 ---------- ----- 69 0x00000002 0 70 SemID Count 71 ---------- ----- 72 0x00000003 1 73 SemID Count 74 ---------- ----- 75 0x00000004 0 76 SemID Count 77 ---------- ----- 78 0x00000005 1 79 SemID Count 80 ---------- ----- 81 0x00000006 0 82``` 83 84**Table 2** Output 85 86<a name="table487mcpsimp"></a> 87<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> 88</th> 89<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> 90</th> 91</tr> 92</thead> 93<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> 94</td> 95<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> 96</td> 97</tr> 98<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> 99</td> 100<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 times that the semaphore is used</p> 101</td> 102</tr> 103</tbody> 104</table> 105 106> **NOTE:** 107>The **ID** value can be in decimal or hexadecimal format. 108>When **ID** is a value within \[0, 1023\], semaphore information of the specified ID is displayed. If the specified semaphore 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. 109 110Example 2: detailed semaphore information 111 112``` 113OHOS # sem fulldata 114Used Semaphore List: 115 SemID Count OriginalCount Creater(TaskEntry) LastAccessTime 116 ------ ------ ------------- ------------------ -------------- 117 0xb 0x0 0x0 0x404978fc 0xa1 118 0xc 0x0 0x0 0x404978fc 0xa1 119 0xd 0x0 0x0 0x404978fc 0x12c 120 0x10 0x0 0x0 0x404978fc 0x195 121 0xf 0x0 0x0 0x404978fc 0x195 122 0x11 0x0 0x0 0x4041a998 0x1d5 123 0x15 0x0 0x0 0x404978fc 0x273 124 0x14 0x0 0x0 0x404978fc 0x273 125 0x18 0x0 0x0 0x404978fc 0x352 126 0x17 0x0 0x0 0x404978fc 0x352 127 0x16 0x0 0x0 0x404978fc 0x352 128 0x1d 0x1 0x1 0x404978fc 0x385 129 0x1e 0x1 0x1 0x404978fc 0x388 130 0x1f 0x1 0x1 0x404978fc 0x38d 131 0x20 0x1 0x1 0x404978fc 0x38f 132 0x21 0x1 0x1 0x404978fc 0x392 133 0x3d 0x1 0x1 0x404978fc 0x395 134 0x3b 0x1 0x1 0x404978fc 0x395 135 0x3c 0x1 0x1 0x404978fc 0x395 136 0x39 0x1 0x1 0x404978fc 0x395 137 0x3a 0x1 0x1 0x404978fc 0x395 138 0x33 0x1 0x1 0x404978fc 0x395 139 0x35 0x1 0x1 0x404978fc 0x395 140 0x34 0x1 0x1 0x404978fc 0x395 141 0x38 0x1 0x1 0x404978fc 0x395 142``` 143 144**Table 3** Output description 145 146<a name="table57783201041"></a> 147<table><thead align="left"><tr id="row12778320943"><th class="cellrowborder" valign="top" width="50%" id="mcps1.2.3.1.1"><p id="p153641444643"><a name="p153641444643"></a><a name="p153641444643"></a>Parameter</p> 148</th> 149<th class="cellrowborder" valign="top" width="50%" id="mcps1.2.3.1.2"><p id="p236413447414"><a name="p236413447414"></a><a name="p236413447414"></a>Description</p> 150</th> 151</tr> 152</thead> 153<tbody><tr id="row14834640646"><td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.1 "><p id="p7829840647"><a name="p7829840647"></a><a name="p7829840647"></a>SemID</p> 154</td> 155<td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.2 "><p id="p118291440244"><a name="p118291440244"></a><a name="p118291440244"></a>Semaphore ID</p> 156</td> 157</tr> 158<tr id="row78346401141"><td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.1 "><p id="p08292401349"><a name="p08292401349"></a><a name="p08292401349"></a>Count</p> 159</td> 160<td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.2 "><p id="p1829104012416"><a name="p1829104012416"></a><a name="p1829104012416"></a>Number of times that the semaphore is used</p> 161</td> 162</tr> 163<tr id="row1883414404411"><td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.1 "><p id="p88291640847"><a name="p88291640847"></a><a name="p88291640847"></a>OriginalCount</p> 164</td> 165<td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.2 "><p id="p282916401148"><a name="p282916401148"></a><a name="p282916401148"></a>Original count of the semaphore</p> 166</td> 167</tr> 168<tr id="row148347401646"><td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.1 "><p id="p1782914401646"><a name="p1782914401646"></a><a name="p1782914401646"></a>Creater</p> 169</td> 170<td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.2 "><p id="p168298407419"><a name="p168298407419"></a><a name="p168298407419"></a>Address of the entry function of the thread used to create the semaphore</p> 171</td> 172</tr> 173<tr id="row783415401340"><td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.1 "><p id="p18829640549"><a name="p18829640549"></a><a name="p18829640549"></a>LastAccessTime</p> 174</td> 175<td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.2 "><p id="p198292406412"><a name="p198292406412"></a><a name="p198292406412"></a>Last time when the semaphore was accessed</p> 176</td> 177</tr> 178</tbody> 179</table> 180 181
