{"id":72459,"date":"2026-02-05T18:05:22","date_gmt":"2026-02-05T10:05:22","guid":{"rendered":"https:\/\/www.wsisp.com\/helps\/72459.html"},"modified":"2026-02-05T18:05:22","modified_gmt":"2026-02-05T10:05:22","slug":"memcpy%e6%b7%b1%e5%ba%a6%e8%a7%a3%e6%9e%90%ef%bc%9aresistance-vs-resistance-%e5%85%b3%e9%94%ae%e5%8c%ba%e5%88%ab","status":"publish","type":"post","link":"https:\/\/www.wsisp.com\/helps\/72459.html","title":{"rendered":"memcpy\u6df1\u5ea6\u89e3\u6790\uff1a`&resistance` vs `resistance` \u5173\u952e\u533a\u522b"},"content":{"rendered":"

memcpy\u6df1\u5ea6\u89e3\u6790：&resistance vs resistance \u5173\u952e\u533a\u522b<\/h2>\n

\u4e00\u3001\u672c\u8d28\u533a\u522b：\u76ee\u6807\u5730\u5740\u7684\u4e0d\u540c\u542b\u4e49<\/h3>\n

1. \u5185\u5b58\u64cd\u4f5c\u793a\u610f\u56fe<\/h4>\n

graph LR
\nS[\u6e90\u6570\u636e] –>|memcpy| D[\u76ee\u6807\u5730\u5740]<\/p>\n

subgraph \u573a\u666f1：memcpy(&resistance, \u2026)
\nA[resistance\u53d8\u91cf] –>|&resistance \u53d6\u5730\u5740| D1[\u53d8\u91cf\u5185\u5b58\u4f4d\u7f6e]
\nend<\/p>\n

subgraph \u573a\u666f2：memcpy(resistance, \u2026)
\nB[resistance\u6307\u9488] –>|resistance \u6307\u9488\u503c| D2[\u6307\u9488\u6307\u5411\u7684\u5185\u5b58\u533a\u57df]
\nend<\/p>\n

2. \u6838\u5fc3\u533a\u522b\u5bf9\u6bd4\u8868<\/h4>\n\n\u7279\u6027memcpy(&resistance, src, size)memcpy(resistance, src, size)<\/tr>\n\n\n\n\n\n\n
\u76ee\u6807\u7c7b\u578b<\/td>\n\u53d8\u91cf\u5730\u5740<\/td>\n\u6307\u9488\u53d8\u91cf<\/td>\n<\/tr>\n
\u64cd\u4f5c\u5bf9\u8c61<\/td>\nresistance\u53d8\u91cf\u672c\u8eab<\/td>\nresistance\u6307\u9488\u6307\u5411\u7684\u5185\u5b58\u533a\u57df<\/td>\n<\/tr>\n
\u5185\u5b58\u5f71\u54cd<\/td>\n\u76f4\u63a5\u4fee\u6539resistance\u7684\u503c<\/td>\n\u4fee\u6539resistance\u6307\u5411\u7684\u6570\u636e<\/td>\n<\/tr>\n
\u5178\u578b\u7528\u9014<\/td>\n\u586b\u5145\u5c40\u90e8\/\u5168\u5c40\u53d8\u91cf<\/td>\n\u586b\u5145\u52a8\u6001\u5206\u914d\u7684\u5185\u5b58<\/td>\n<\/tr>\n
\u98ce\u9669<\/td>\n\u53d8\u91cf\u5927\u5c0f\u4e0d\u8db3\u5bfc\u81f4\u6ea2\u51fa<\/td>\n\u6307\u9488\u672a\u521d\u59cb\u5316\u5bfc\u81f4\u5d29\u6e83<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u4e8c\u3001\u4ee3\u7801\u5b9e\u4f8b\u6df1\u5ea6\u5206\u6790<\/h3>\n

1. \u53d8\u91cf\u7c7b\u578b\u5b9a\u4e49\u793a\u4f8b<\/h4>\n

\/\/ \u60c5\u51b51：resistance\u662f\u666e\u901a\u53d8\u91cf<\/span>
\nuint32_t<\/span> resistance;<\/span>\/\/ 4\u5b57\u8282\u53d8\u91cf<\/span><\/p>\n

\/\/ \u60c5\u51b52：resistance\u662f\u6307\u9488<\/span>
\nuint32_t<\/span>*<\/span> resistance;<\/span> \/\/ \u6307\u5411uint32_t\u7684\u6307\u9488<\/span><\/p>\n

2. \u6b63\u786e\u7528\u6cd5\u793a\u4f8b<\/h4>\n

\/\/ \u793a\u4f8b1：\u4f7f\u7528&\u64cd\u4f5c\u7b26（resistance\u662f\u53d8\u91cf）<\/span>
\nuint32_t<\/span> resistance;<\/span> \/\/ \u58f0\u660e\u4e00\u4e2a4\u5b57\u8282\u53d8\u91cf<\/span>
\nmemcpy<\/span>(<\/span>&<\/span>resistance,<\/span> &<\/span>usRegHoldingBuf[<\/span>res_reg]<\/span>,<\/span> 4<\/span>)<\/span>;<\/span>
\n\/\/ \u6b63\u786e：\u5c064\u5b57\u8282\u6570\u636e\u590d\u5236\u5230resistance\u53d8\u91cf<\/span><\/p>\n

\/\/ \u793a\u4f8b2：\u76f4\u63a5\u4f7f\u7528\u6307\u9488（resistance\u662f\u6307\u9488）<\/span>
\nuint32_t<\/span>*<\/span> resistance =<\/span> malloc<\/span>(<\/span>sizeof<\/span>(<\/span>uint32_t<\/span>)<\/span>)<\/span>;<\/span> \/\/ \u5206\u914d\u5185\u5b58<\/span>
\nmemcpy<\/span>(<\/span>resistance,<\/span> &<\/span>usRegHoldingBuf[<\/span>res_reg]<\/span>,<\/span> 4<\/span>)<\/span>;<\/span>
\n\/\/ \u6b63\u786e：\u5c06\u6570\u636e\u590d\u5236\u5230\u6307\u9488\u6307\u5411\u7684\u5185\u5b58\u533a\u57df<\/span><\/p>\n

3. \u9519\u8bef\u7528\u6cd5\u53ca\u540e\u679c<\/h4>\n

\/\/ \u9519\u8bef\u793a\u4f8b1：\u53d8\u91cf\u8bef\u7528\u4e3a\u6307\u9488<\/span>
\nuint32_t<\/span> resistance;<\/span>
\nmemcpy<\/span>(<\/span>resistance,<\/span> &<\/span>usRegHoldingBuf[<\/span>res_reg]<\/span>,<\/span> 4<\/span>)<\/span>;<\/span>
\n\/\/ \u5d29\u6e83！\u5c06\u53d8\u91cf\u503c\u5f53\u4f5c\u5730\u5740\u8bbf\u95ee（resistance\u5305\u542b\u968f\u673a\u503c）<\/span><\/p>\n

\/\/ \u9519\u8bef\u793a\u4f8b2：\u6307\u9488\u672a\u521d\u59cb\u5316<\/span>
\nuint32_t<\/span>*<\/span> resistance;<\/span> \/\/ \u672a\u521d\u59cb\u5316<\/span>
\nmemcpy<\/span>(<\/span>resistance,<\/span> &<\/span>usRegHoldingBuf[<\/span>res_reg]<\/span>,<\/span> 4<\/span>)<\/span>;<\/span>
\n\/\/ \u5d29\u6e83！\u8bbf\u95ee\u968f\u673a\u5185\u5b58\u5730\u5740（\u91ce\u6307\u9488）<\/span><\/p>\n

\/\/ \u9519\u8bef\u793a\u4f8b3：\u5927\u5c0f\u4e0d\u5339\u914d<\/span>
\nfloat<\/span> resistance;<\/span> \/\/ 4\u5b57\u8282\u4f46\u7c7b\u578b\u4e0d\u540c<\/span>
\nmemcpy<\/span>(<\/span>&<\/span>resistance,<\/span> &<\/span>usRegHoldingBuf[<\/span>res_reg]<\/span>,<\/span> 4<\/span>)<\/span>;<\/span>
\n\/\/ \u5371\u9669！\u6309\u5b57\u8282\u590d\u5236\u53ef\u80fd\u7834\u574f\u6d6e\u70b9\u8868\u793a<\/span><\/p>\n

\u4e09\u3001\u5185\u5b58\u5e03\u5c40\u8be6\u89e3<\/h3>\n

1. \u6b63\u786e\u60c5\u51b5\u5185\u5b58\u5e03\u5c40<\/h4>\n

#mermaid-svg-Rszd5ykyIgJgAXGa{font-family:\\”trebuchet ms\\”,verdana,arial,sans-serif;font-size:16px;fill:#333;}@keyframes edge-animation-frame{from{stroke-dashoffset:0;}}@keyframes dash{to{stroke-dashoffset:0;}}#mermaid-svg-Rszd5ykyIgJgAXGa .edge-animation-slow{stroke-dasharray:9,5!important;stroke-dashoffset:900;animation:dash 50s linear infinite;stroke-linecap:round;}#mermaid-svg-Rszd5ykyIgJgAXGa .edge-animation-fast{stroke-dasharray:9,5!important;stroke-dashoffset:900;animation:dash 20s linear infinite;stroke-linecap:round;}#mermaid-svg-Rszd5ykyIgJgAXGa .error-icon{fill:#552222;}#mermaid-svg-Rszd5ykyIgJgAXGa .error-text{fill:#552222;stroke:#552222;}#mermaid-svg-Rszd5ykyIgJgAXGa .edge-thickness-normal{stroke-width:1px;}#mermaid-svg-Rszd5ykyIgJgAXGa .edge-thickness-thick{stroke-width:3.5px;}#mermaid-svg-Rszd5ykyIgJgAXGa .edge-pattern-solid{stroke-dasharray:0;}#mermaid-svg-Rszd5ykyIgJgAXGa .edge-thickness-invisible{stroke-width:0;fill:none;}#mermaid-svg-Rszd5ykyIgJgAXGa .edge-pattern-dashed{stroke-dasharray:3;}#mermaid-svg-Rszd5ykyIgJgAXGa .edge-pattern-dotted{stroke-dasharray:2;}#mermaid-svg-Rszd5ykyIgJgAXGa .marker{fill:#333333;stroke:#333333;}#mermaid-svg-Rszd5ykyIgJgAXGa .marker.cross{stroke:#333333;}#mermaid-svg-Rszd5ykyIgJgAXGa svg{font-family:\\”trebuchet ms\\”,verdana,arial,sans-serif;font-size:16px;}#mermaid-svg-Rszd5ykyIgJgAXGa p{margin:0;}#mermaid-svg-Rszd5ykyIgJgAXGa .label{font-family:\\”trebuchet ms\\”,verdana,arial,sans-serif;color:#333;}#mermaid-svg-Rszd5ykyIgJgAXGa .cluster-label text{fill:#333;}#mermaid-svg-Rszd5ykyIgJgAXGa .cluster-label span{color:#333;}#mermaid-svg-Rszd5ykyIgJgAXGa .cluster-label span p{background-color:transparent;}#mermaid-svg-Rszd5ykyIgJgAXGa .label text,#mermaid-svg-Rszd5ykyIgJgAXGa span{fill:#333;color:#333;}#mermaid-svg-Rszd5ykyIgJgAXGa .node rect,#mermaid-svg-Rszd5ykyIgJgAXGa .node circle,#mermaid-svg-Rszd5ykyIgJgAXGa .node ellipse,#mermaid-svg-Rszd5ykyIgJgAXGa .node polygon,#mermaid-svg-Rszd5ykyIgJgAXGa .node path{fill:#ECECFF;stroke:#9370DB;stroke-width:1px;}#mermaid-svg-Rszd5ykyIgJgAXGa .rough-node .label text,#mermaid-svg-Rszd5ykyIgJgAXGa .node .label text,#mermaid-svg-Rszd5ykyIgJgAXGa .image-shape .label,#mermaid-svg-Rszd5ykyIgJgAXGa .icon-shape .label{text-anchor:middle;}#mermaid-svg-Rszd5ykyIgJgAXGa .node .katex path{fill:#000;stroke:#000;stroke-width:1px;}#mermaid-svg-Rszd5ykyIgJgAXGa .rough-node .label,#mermaid-svg-Rszd5ykyIgJgAXGa .node .label,#mermaid-svg-Rszd5ykyIgJgAXGa .image-shape .label,#mermaid-svg-Rszd5ykyIgJgAXGa .icon-shape .label{text-align:center;}#mermaid-svg-Rszd5ykyIgJgAXGa .node.clickable{cursor:pointer;}#mermaid-svg-Rszd5ykyIgJgAXGa .root .anchor path{fill:#333333!important;stroke-width:0;stroke:#333333;}#mermaid-svg-Rszd5ykyIgJgAXGa .arrowheadPath{fill:#333333;}#mermaid-svg-Rszd5ykyIgJgAXGa .edgePath .path{stroke:#333333;stroke-width:2.0px;}#mermaid-svg-Rszd5ykyIgJgAXGa .flowchart-link{stroke:#333333;fill:none;}#mermaid-svg-Rszd5ykyIgJgAXGa .edgeLabel{background-color:rgba(232,232,232, 0.8);text-align:center;}#mermaid-svg-Rszd5ykyIgJgAXGa .edgeLabel p{background-color:rgba(232,232,232, 0.8);}#mermaid-svg-Rszd5ykyIgJgAXGa .edgeLabel rect{opacity:0.5;background-color:rgba(232,232,232, 0.8);fill:rgba(232,232,232, 0.8);}#mermaid-svg-Rszd5ykyIgJgAXGa .labelBkg{background-color:rgba(232, 232, 232, 0.5);}#mermaid-svg-Rszd5ykyIgJgAXGa .cluster rect{fill:#ffffde;stroke:#aaaa33;stroke-width:1px;}#mermaid-svg-Rszd5ykyIgJgAXGa .cluster text{fill:#333;}#mermaid-svg-Rszd5ykyIgJgAXGa .cluster span{color:#333;}#mermaid-svg-Rszd5ykyIgJgAXGa div.mermaidTooltip{position:absolute;text-align:center;max-width:200px;padding:2px;font-family:\\”trebuchet ms\\”,verdana,arial,sans-serif;font-size:12px;background:hsl(80, 100%, 96.2745098039%);border:1px solid #aaaa33;border-radius:2px;pointer-events:none;z-index:100;}#mermaid-svg-Rszd5ykyIgJgAXGa .flowchartTitleText{text-anchor:middle;font-size:18px;fill:#333;}#mermaid-svg-Rszd5ykyIgJgAXGa rect.text{fill:none;stroke-width:0;}#mermaid-svg-Rszd5ykyIgJgAXGa .icon-shape,#mermaid-svg-Rszd5ykyIgJgAXGa .image-shape{background-color:rgba(232,232,232, 0.8);text-align:center;}#mermaid-svg-Rszd5ykyIgJgAXGa .icon-shape p,#mermaid-svg-Rszd5ykyIgJgAXGa .image-shape p{background-color:rgba(232,232,232, 0.8);padding:2px;}#mermaid-svg-Rszd5ykyIgJgAXGa .icon-shape rect,#mermaid-svg-Rszd5ykyIgJgAXGa .image-shape rect{opacity:0.5;background-color:rgba(232,232,232, 0.8);fill:rgba(232,232,232, 0.8);}#mermaid-svg-Rszd5ykyIgJgAXGa .label-icon{display:inline-block;height:1em;overflow:visible;vertical-align:-0.125em;}#mermaid-svg-Rszd5ykyIgJgAXGa .node .label-icon path{fill:currentColor;stroke:revert;stroke-width:revert;}#mermaid-svg-Rszd5ykyIgJgAXGa :root{–mermaid-font-family:\\”trebuchet ms\\”,verdana,arial,sans-serif;}<\/p>\n

Modbus\u5bc4\u5b58\u5668<\/p>\n

<\/span><\/p>\n

\u6808\u5185\u5b58<\/p>\n

<\/span><\/p>\n

&resistance<\/p>\n

<\/span><\/span><\/p>\n

memcpy\u64cd\u4f5c<\/p>\n

<\/span><\/span><\/p>\n

resistance\u53d8\u91cf<\/p>\n

<\/span><\/p>\n

0x1000<\/p>\n

<\/span><\/p>\n

usRegHoldingBuf<\/p>\n

<\/span><\/p>\n

0x2000-0x2003<\/p>\n

<\/span><\/p>\n

\u590d\u52364\u5b57\u8282\u6570\u636e<\/p>\n

<\/span><\/p>\n

2. \u9519\u8bef\u60c5\u51b5\u5185\u5b58\u5e03\u5c40<\/h4>\n

#mermaid-svg-P6Iy0rsBpEmc7cTs{font-family:\\”trebuchet ms\\”,verdana,arial,sans-serif;font-size:16px;fill:#333;}@keyframes edge-animation-frame{from{stroke-dashoffset:0;}}@keyframes dash{to{stroke-dashoffset:0;}}#mermaid-svg-P6Iy0rsBpEmc7cTs .edge-animation-slow{stroke-dasharray:9,5!important;stroke-dashoffset:900;animation:dash 50s linear infinite;stroke-linecap:round;}#mermaid-svg-P6Iy0rsBpEmc7cTs .edge-animation-fast{stroke-dasharray:9,5!important;stroke-dashoffset:900;animation:dash 20s linear infinite;stroke-linecap:round;}#mermaid-svg-P6Iy0rsBpEmc7cTs .error-icon{fill:#552222;}#mermaid-svg-P6Iy0rsBpEmc7cTs .error-text{fill:#552222;stroke:#552222;}#mermaid-svg-P6Iy0rsBpEmc7cTs .edge-thickness-normal{stroke-width:1px;}#mermaid-svg-P6Iy0rsBpEmc7cTs .edge-thickness-thick{stroke-width:3.5px;}#mermaid-svg-P6Iy0rsBpEmc7cTs .edge-pattern-solid{stroke-dasharray:0;}#mermaid-svg-P6Iy0rsBpEmc7cTs .edge-thickness-invisible{stroke-width:0;fill:none;}#mermaid-svg-P6Iy0rsBpEmc7cTs .edge-pattern-dashed{stroke-dasharray:3;}#mermaid-svg-P6Iy0rsBpEmc7cTs .edge-pattern-dotted{stroke-dasharray:2;}#mermaid-svg-P6Iy0rsBpEmc7cTs .marker{fill:#333333;stroke:#333333;}#mermaid-svg-P6Iy0rsBpEmc7cTs .marker.cross{stroke:#333333;}#mermaid-svg-P6Iy0rsBpEmc7cTs svg{font-family:\\”trebuchet ms\\”,verdana,arial,sans-serif;font-size:16px;}#mermaid-svg-P6Iy0rsBpEmc7cTs p{margin:0;}#mermaid-svg-P6Iy0rsBpEmc7cTs .label{font-family:\\”trebuchet ms\\”,verdana,arial,sans-serif;color:#333;}#mermaid-svg-P6Iy0rsBpEmc7cTs .cluster-label text{fill:#333;}#mermaid-svg-P6Iy0rsBpEmc7cTs .cluster-label span{color:#333;}#mermaid-svg-P6Iy0rsBpEmc7cTs .cluster-label span p{background-color:transparent;}#mermaid-svg-P6Iy0rsBpEmc7cTs .label text,#mermaid-svg-P6Iy0rsBpEmc7cTs span{fill:#333;color:#333;}#mermaid-svg-P6Iy0rsBpEmc7cTs .node rect,#mermaid-svg-P6Iy0rsBpEmc7cTs .node circle,#mermaid-svg-P6Iy0rsBpEmc7cTs .node ellipse,#mermaid-svg-P6Iy0rsBpEmc7cTs .node polygon,#mermaid-svg-P6Iy0rsBpEmc7cTs .node path{fill:#ECECFF;stroke:#9370DB;stroke-width:1px;}#mermaid-svg-P6Iy0rsBpEmc7cTs .rough-node .label text,#mermaid-svg-P6Iy0rsBpEmc7cTs .node .label text,#mermaid-svg-P6Iy0rsBpEmc7cTs .image-shape .label,#mermaid-svg-P6Iy0rsBpEmc7cTs .icon-shape .label{text-anchor:middle;}#mermaid-svg-P6Iy0rsBpEmc7cTs .node .katex path{fill:#000;stroke:#000;stroke-width:1px;}#mermaid-svg-P6Iy0rsBpEmc7cTs .rough-node .label,#mermaid-svg-P6Iy0rsBpEmc7cTs .node .label,#mermaid-svg-P6Iy0rsBpEmc7cTs .image-shape .label,#mermaid-svg-P6Iy0rsBpEmc7cTs .icon-shape .label{text-align:center;}#mermaid-svg-P6Iy0rsBpEmc7cTs .node.clickable{cursor:pointer;}#mermaid-svg-P6Iy0rsBpEmc7cTs .root .anchor path{fill:#333333!important;stroke-width:0;stroke:#333333;}#mermaid-svg-P6Iy0rsBpEmc7cTs .arrowheadPath{fill:#333333;}#mermaid-svg-P6Iy0rsBpEmc7cTs .edgePath .path{stroke:#333333;stroke-width:2.0px;}#mermaid-svg-P6Iy0rsBpEmc7cTs .flowchart-link{stroke:#333333;fill:none;}#mermaid-svg-P6Iy0rsBpEmc7cTs .edgeLabel{background-color:rgba(232,232,232, 0.8);text-align:center;}#mermaid-svg-P6Iy0rsBpEmc7cTs .edgeLabel p{background-color:rgba(232,232,232, 0.8);}#mermaid-svg-P6Iy0rsBpEmc7cTs .edgeLabel rect{opacity:0.5;background-color:rgba(232,232,232, 0.8);fill:rgba(232,232,232, 0.8);}#mermaid-svg-P6Iy0rsBpEmc7cTs .labelBkg{background-color:rgba(232, 232, 232, 0.5);}#mermaid-svg-P6Iy0rsBpEmc7cTs .cluster rect{fill:#ffffde;stroke:#aaaa33;stroke-width:1px;}#mermaid-svg-P6Iy0rsBpEmc7cTs .cluster text{fill:#333;}#mermaid-svg-P6Iy0rsBpEmc7cTs .cluster span{color:#333;}#mermaid-svg-P6Iy0rsBpEmc7cTs div.mermaidTooltip{position:absolute;text-align:center;max-width:200px;padding:2px;font-family:\\”trebuchet ms\\”,verdana,arial,sans-serif;font-size:12px;background:hsl(80, 100%, 96.2745098039%);border:1px solid #aaaa33;border-radius:2px;pointer-events:none;z-index:100;}#mermaid-svg-P6Iy0rsBpEmc7cTs .flowchartTitleText{text-anchor:middle;font-size:18px;fill:#333;}#mermaid-svg-P6Iy0rsBpEmc7cTs rect.text{fill:none;stroke-width:0;}#mermaid-svg-P6Iy0rsBpEmc7cTs .icon-shape,#mermaid-svg-P6Iy0rsBpEmc7cTs .image-shape{background-color:rgba(232,232,232, 0.8);text-align:center;}#mermaid-svg-P6Iy0rsBpEmc7cTs .icon-shape p,#mermaid-svg-P6Iy0rsBpEmc7cTs .image-shape p{background-color:rgba(232,232,232, 0.8);padding:2px;}#mermaid-svg-P6Iy0rsBpEmc7cTs .icon-shape rect,#mermaid-svg-P6Iy0rsBpEmc7cTs .image-shape rect{opacity:0.5;background-color:rgba(232,232,232, 0.8);fill:rgba(232,232,232, 0.8);}#mermaid-svg-P6Iy0rsBpEmc7cTs .label-icon{display:inline-block;height:1em;overflow:visible;vertical-align:-0.125em;}#mermaid-svg-P6Iy0rsBpEmc7cTs .node .label-icon path{fill:currentColor;stroke:revert;stroke-width:revert;}#mermaid-svg-P6Iy0rsBpEmc7cTs :root{–mermaid-font-family:\\”trebuchet ms\\”,verdana,arial,sans-serif;}<\/p>\n

Modbus\u5bc4\u5b58\u5668<\/p>\n

<\/span><\/span><\/p>\n

memcpy\u64cd\u4f5c<\/p>\n

<\/span><\/span><\/p>\n

\u6808\u5185\u5b58<\/p>\n

<\/span><\/p>\n

\u503c=0xDEADBEEF<\/p>\n

<\/span><\/p>\n

resistance\u53d8\u91cf<\/p>\n

<\/span><\/p>\n

0x1000<\/p>\n

<\/span><\/p>\n

usRegHoldingBuf<\/p>\n

<\/span><\/p>\n

0x2000-0x2003<\/p>\n

<\/span><\/p>\n

0xDEADBEEF<\/p>\n

<\/span><\/p>\n

\u5c1d\u8bd5\u5199\u5165<\/p>\n

<\/span><\/p>\n

\u56db\u3001\u5b9e\u6218\u5e94\u7528\u573a\u666f<\/h3>\n

1. Modbus\u6570\u636e\u5904\u7406（\u63a8\u8350\u65b9\u6848）<\/h4>\n

\/\/ \u5b89\u5168\u8bfb\u53d632\u4f4d\u5bc4\u5b58\u5668\u503c<\/span>
\nuint32_t<\/span> read_modbus_register<\/span>(<\/span>uint16_t<\/span> reg_index)<\/span> {<\/span>
\nuint32_t<\/span> value;<\/span><\/p>\n

\/\/ \u68c0\u67e5\u5bc4\u5b58\u5668\u8303\u56f4<\/span>
\nif<\/span>(<\/span>reg_index >=<\/span> MAX_REGISTERS –<\/span> 3<\/span>)<\/span> {<\/span>
\nreturn<\/span> 0<\/span>;<\/span> \/\/ \u9519\u8bef\u5904\u7406<\/span>
\n}<\/span><\/p>\n

\/\/ \u4f7f\u7528memcpy\u907f\u514d\u5b57\u8282\u5e8f\u95ee\u9898<\/span>
\nmemcpy<\/span>(<\/span>&<\/span>value,<\/span> &<\/span>usRegHoldingBuf[<\/span>reg_index]<\/span>,<\/span> 4<\/span>)<\/span>;<\/span><\/p>\n

return<\/span> ntohl<\/span>(<\/span>value)<\/span>;<\/span> \/\/ \u8f6c\u6362\u5b57\u8282\u5e8f<\/span>
\n}<\/span><\/p>\n

2. \u52a8\u6001\u6570\u636e\u5904\u7406<\/h4>\n

\/\/ \u521b\u5efa\u5bc4\u5b58\u5668\u6570\u636e\u526f\u672c<\/span>
\nuint32_t<\/span>*<\/span> create_register_copy<\/span>(<\/span>uint16_t<\/span> start,<\/span> uint16_t<\/span> count)<\/span> {<\/span>
\nsize_t<\/span> size =<\/span> count *<\/span> sizeof<\/span>(<\/span>uint16_t<\/span>)<\/span>;<\/span>
\nuint32_t<\/span>*<\/span> buffer =<\/span> malloc<\/span>(<\/span>size)<\/span>;<\/span><\/p>\n

if<\/span>(<\/span>!<\/span>buffer)<\/span> return<\/span> NULL<\/span>;<\/span><\/p>\n

\/\/ \u76f4\u63a5\u4f7f\u7528\u6307\u9488\u590d\u5236\u6570\u636e<\/span>
\nmemcpy<\/span>(<\/span>buffer,<\/span> &<\/span>usRegHoldingBuf[<\/span>start]<\/span>,<\/span> size)<\/span>;<\/span><\/p>\n

return<\/span> buffer;<\/span>
\n}<\/span><\/p>\n

\u4e94\u3001\u5e38\u89c1\u95ee\u9898\u89e3\u51b3\u65b9\u6848<\/h3>\n

1. \u7c7b\u578b\u5b89\u5168\u589e\u5f3a<\/h4>\n

\/\/ \u7c7b\u578b\u5b89\u5168\u7684memcpy\u5c01\u88c5<\/span>
\ntemplate<<\/span>typename T><\/span>
\nvoid<\/span> safe_memcpy<\/span>(<\/span>T&<\/span> dest,<\/span> const<\/span> void<\/span>*<\/span> src)<\/span> {<\/span>
\nstatic_assert<\/span>(<\/span>!<\/span>std::<\/span>is_pointer<<\/span>T><\/span>::<\/span>value,<\/span>
\n"Use pointer version for pointer types"<\/span>)<\/span>;<\/span>
\nmemcpy<\/span>(<\/span>&<\/span>dest,<\/span> src,<\/span> sizeof<\/span>(<\/span>T)<\/span>)<\/span>;<\/span>
\n}<\/span><\/p>\n

\/\/ \u6307\u9488\u7248\u672c\u91cd\u8f7d<\/span>
\ntemplate<<\/span>typename T><\/span>
\nvoid<\/span> safe_memcpy<\/span>(<\/span>T*<\/span> dest,<\/span> const<\/span> void<\/span>*<\/span> src,<\/span> size_t<\/span> count =<\/span> 1<\/span>)<\/span> {<\/span>
\nmemcpy<\/span>(<\/span>dest,<\/span> src,<\/span> count *<\/span> sizeof<\/span>(<\/span>T)<\/span>)<\/span>;<\/span>
\n}<\/span><\/p>\n

\/\/ \u4f7f\u7528\u793a\u4f8b<\/span>
\nuint32_t<\/span> resistance;<\/span>
\nsafe_memcpy<\/span>(<\/span>resistance,<\/span> &<\/span>usRegHoldingBuf[<\/span>res_reg]<\/span>)<\/span>;<\/span> \/\/ \u81ea\u52a8\u63a8\u65ad\u5927\u5c0f<\/span><\/p>\n

uint32_t<\/span>*<\/span> pRes =<\/span> malloc<\/span>(<\/span>sizeof<\/span>(<\/span>uint32_t<\/span>)<\/span>)<\/span>;<\/span>
\nsafe_memcpy<\/span>(<\/span>pRes,<\/span> &<\/span>usRegHoldingBuf[<\/span>res_reg]<\/span>)<\/span>;<\/span> \/\/ \u6307\u9488\u7248\u672c<\/span><\/p>\n

2. \u5b57\u8282\u5e8f\u5904\u7406<\/h4>\n

\/\/ \u5904\u7406\u5927\u7aef\u5e8f\u5b58\u50a8\u7684\u5bc4\u5b58\u5668\u6570\u636e<\/span>
\nuint32_t<\/span> read_big_endian<\/span>(<\/span>const<\/span> uint16_t<\/span>*<\/span> reg_ptr)<\/span> {<\/span>
\nuint32_t<\/span> result;<\/span>
\nuint8_t<\/span>*<\/span> bytes =<\/span> (<\/span>uint8_t<\/span>*<\/span>)<\/span>&<\/span>result;<\/span><\/p>\n

\/\/ \u624b\u52a8\u5904\u7406\u5b57\u8282\u5e8f<\/span>
\nbytes[<\/span>0<\/span>]<\/span> =<\/span> (<\/span>reg_ptr[<\/span>0<\/span>]<\/span> >><\/span> 8<\/span>)<\/span> &<\/span> 0xFF<\/span>;<\/span>
\nbytes[<\/span>1<\/span>]<\/span> =<\/span> reg_ptr[<\/span>0<\/span>]<\/span> &<\/span> 0xFF<\/span>;<\/span>
\nbytes[<\/span>2<\/span>]<\/span> =<\/span> (<\/span>reg_ptr[<\/span>1<\/span>]<\/span> >><\/span> 8<\/span>)<\/span> &<\/span> 0xFF<\/span>;<\/span>
\nbytes[<\/span>3<\/span>]<\/span> =<\/span> reg_ptr[<\/span>1<\/span>]<\/span> &<\/span> 0xFF<\/span>;<\/span><\/p>\n

return<\/span> result;<\/span>
\n}<\/span><\/p>\n

\/\/ \u4f7f\u7528memcpy\u7684\u4f18\u5316\u7248\u672c<\/span>
\nuint32_t<\/span> read_big_endian_optimized<\/span>(<\/span>const<\/span> uint16_t<\/span>*<\/span> reg_ptr)<\/span> {<\/span>
\nunion<\/span> {<\/span>
\nuint32_t<\/span> value;<\/span>
\nuint16_t<\/span> words[<\/span>2<\/span>]<\/span>;<\/span>
\n}<\/span> converter;<\/span><\/p>\n

memcpy<\/span>(<\/span>converter.<\/span>words,<\/span> reg_ptr,<\/span> 4<\/span>)<\/span>;<\/span>
\nreturn<\/span> (<\/span>converter.<\/span>words[<\/span>0<\/span>]<\/span> <<<\/span> 16<\/span>)<\/span> |<\/span> converter.<\/span>words[<\/span>1<\/span>]<\/span>;<\/span>
\n}<\/span><\/p>\n

3. \u8fb9\u754c\u68c0\u67e5\u5f3a\u5316<\/h4>\n

\/\/ \u5e26\u8fb9\u754c\u68c0\u67e5\u7684\u5b89\u5168\u590d\u5236<\/span>
\nbool safe_register_copy<\/span>(<\/span>void<\/span>*<\/span> dest,<\/span> size_t<\/span> dest_size,<\/span>
\nuint16_t<\/span> reg_index,<\/span> size_t<\/span> copy_size)<\/span> {<\/span>
\n\/\/ \u68c0\u67e5\u6e90\u8fb9\u754c<\/span>
\nif<\/span>(<\/span>reg_index +<\/span> (<\/span>copy_size\/<\/span>2<\/span>)<\/span> ><\/span> MAX_REGISTERS)<\/span> {<\/span>
\nreturn<\/span> false;<\/span>
\n}<\/span><\/p>\n

\/\/ \u68c0\u67e5\u76ee\u6807\u5927\u5c0f<\/span>
\nif<\/span>(<\/span>dest_size <<\/span> copy_size)<\/span> {<\/span>
\nreturn<\/span> false;<\/span>
\n}<\/span><\/p>\n

memcpy<\/span>(<\/span>dest,<\/span> &<\/span>usRegHoldingBuf[<\/span>reg_index]<\/span>,<\/span> copy_size)<\/span>;<\/span>
\nreturn<\/span> true;<\/span>
\n}<\/span><\/p>\n

\u516d\u3001\u8c03\u8bd5\u6280\u5de7\u4e0e\u9a8c\u8bc1\u65b9\u6cd5<\/h3>\n

1. \u5185\u5b58\u65ad\u70b9\u8bbe\u7f6e<\/h4>\n

\/\/ GDB\u8c03\u8bd5\u793a\u4f8b<\/span>
\n(<\/span>gdb)<\/span> p &<\/span>resistance\/\/ \u67e5\u770b\u53d8\u91cf\u5730\u5740<\/span>
\n$1<\/span> =<\/span> (<\/span>uint32_t<\/span> *<\/span>)<\/span> 0x7fffffffdcbc<\/span><\/p>\n

(<\/span>gdb)<\/span> watch *<\/span>(<\/span>uint32_t<\/span>*<\/span>)<\/span>0x7fffffffdcbc<\/span>\/\/ \u8bbe\u7f6e\u5185\u5b58\u5199\u5165\u65ad\u70b9<\/span>
\nHardware watchpoint 2<\/span>:<\/span> *<\/span>(<\/span>uint32_t<\/span>*<\/span>)<\/span>0x7fffffffdcbc<\/span><\/p>\n

(<\/span>gdb)<\/span> p resistance\/\/ \u67e5\u770b\u6307\u9488\u503c<\/span>
\n$2<\/span> =<\/span> (<\/span>uint32_t<\/span> *<\/span>)<\/span> 0x5555555592a0<\/span><\/p>\n

(<\/span>gdb)<\/span> watch *<\/span>(<\/span>uint32_t<\/span>*<\/span>)<\/span>0x5555555592a0<\/span>\/\/ \u8bbe\u7f6e\u6307\u9488\u6307\u5411\u5185\u5b58\u7684\u65ad\u70b9<\/span><\/p>\n

2. \u8fd0\u884c\u65f6\u68c0\u6d4b<\/h4>\n

\/\/ \u6dfb\u52a0\u8c03\u8bd5\u68c0\u67e5<\/span>
\n#<\/span>define<\/span> DEBUG_MEMCPY<\/span>(<\/span>dest,<\/span> src,<\/span> size)<\/span> do<\/span> {<\/span> <\/span>\\\\<\/span>
\nprintf<\/span>(<\/span><\/span>"memcpy: %p -> %p, size=%zu\\\\n"<\/span>,<\/span> src,<\/span> dest,<\/span> size)<\/span>;<\/span> <\/span>\\\\<\/span>
\nif<\/span>(<\/span>(<\/span>(<\/span>uintptr_t<\/span>)<\/span>dest <<\/span> 0x1000<\/span>)<\/span> ||<\/span> (<\/span>(<\/span>uintptr_t<\/span>)<\/span>src <<\/span> 0x1000<\/span>)<\/span>)<\/span> {<\/span> <\/span>\\\\<\/span>
\nprintf<\/span>(<\/span><\/span>"ERROR: Invalid memory access!\\\\n"<\/span>)<\/span>;<\/span> <\/span>\\\\<\/span>
\nabort<\/span>(<\/span>)<\/span>;<\/span> <\/span>\\\\<\/span>
\n}<\/span> <\/span>\\\\<\/span>
\nmemcpy<\/span>(<\/span>dest,<\/span> src,<\/span> size)<\/span>;<\/span> <\/span>\\\\<\/span>
\n}<\/span> while<\/span>(<\/span>0<\/span>)<\/span><\/span><\/span><\/p>\n

\/\/ \u4f7f\u7528\u793a\u4f8b<\/span>
\nDEBUG_MEMCPY<\/span>(<\/span>&<\/span>resistance,<\/span> &<\/span>usRegHoldingBuf[<\/span>res_reg]<\/span>,<\/span> 4<\/span>)<\/span>;<\/span><\/p>\n

\u4e03\u3001\u6700\u4f73\u5b9e\u8df5\u603b\u7ed3<\/h3>\n

1. \u9009\u62e9\u6307\u5357<\/h4>\n

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\u666e\u901a\u53d8\u91cf<\/p>\n

<\/span><\/p>\n

\u6307\u9488\u53d8\u91cf<\/p>\n

<\/span><\/p>\n

\u6570\u7ec4<\/p>\n

<\/span><\/span><\/span><\/span><\/p>\n

\u9700\u8981\u590d\u5236\u6570\u636e<\/p>\n

<\/span><\/p>\n

\u76ee\u6807\u662f\u4ec0\u4e48\u7c7b\u578b？<\/p>\n

<\/span><\/p>\n

\u4f7f\u7528 & \u53d6\u5730\u5740\u7b26<\/p>\n

<\/span><\/p>\n

\u76f4\u63a5\u4f7f\u7528\u6307\u9488<\/p>\n

<\/span><\/p>\n

\u4f7f\u7528\u6570\u7ec4\u540d<\/p>\n

<\/span><\/p>\n

\u786e\u4fdd\u53d8\u91cf\u5927\u5c0f\u8db3\u591f<\/p>\n

<\/span><\/p>\n

\u786e\u4fdd\u6307\u9488\u5df2\u521d\u59cb\u5316<\/p>\n

<\/span><\/p>\n

\u786e\u4fdd\u4e0d\u8d8a\u754c<\/p>\n

<\/span><\/p>\n

2. \u9ec4\u91d1\u6cd5\u5219<\/h4>\n
  • \u5730\u5740\u64cd\u4f5c\u7b26\u89c4\u5219：<\/li>\n
      \n
    • \u5bf9\u666e\u901a\u53d8\u91cf\u4f7f\u7528 &<\/li>\n
    • \u5bf9\u6307\u9488\u53d8\u91cf\u76f4\u63a5\u4f7f\u7528<\/li>\n
    • \u5bf9\u6570\u7ec4\u4f7f\u7528\u6570\u7ec4\u540d（\u7b49\u6548\u4e8e\u6307\u9488）<\/li>\n<\/ul>\n
    • \u5b89\u5168\u68c0\u67e5\u6e05\u5355：<\/li>\n

      if<\/span>(<\/span>\u4f7f\u7528\u6307\u9488)<\/span> {<\/span>
      \n\u786e\u4fdd\u6307\u9488\u5df2\u521d\u59cb\u5316(<\/span>)<\/span>;<\/span>
      \n\u786e\u4fdd\u6307\u9488\u6307\u5411\u7684\u5185\u5b58\u6709\u6548(<\/span>)<\/span>;<\/span>
      \n}<\/span> else<\/span> {<\/span>
      \n\u786e\u4fdd\u76ee\u6807\u53d8\u91cf\u5927\u5c0f\u8db3\u591f(<\/span>)<\/span>;<\/span>
      \n}<\/span>
      \n\u786e\u4fdd\u6e90\u6570\u636e\u53ef\u8bbf\u95ee(<\/span>)<\/span>;<\/span>
      \n\u786e\u4fdd\u590d\u5236\u5927\u5c0f\u6b63\u786e(<\/span>)<\/span>;<\/span><\/p>\n

    • \u9632\u5fa1\u6027\u7f16\u7a0b：<\/li>\n

      \/\/ \u5b89\u5168\u590d\u5236\u6a21\u677f<\/span>
      \nvoid<\/span> safe_register_copy<\/span>(<\/span>void<\/span>*<\/span> dest,<\/span> uint16_t<\/span>*<\/span> src,<\/span> size_t<\/span> size)<\/span> {<\/span>
      \nassert<\/span>(<\/span>dest !=<\/span> NULL<\/span>)<\/span>;<\/span>
      \nassert<\/span>(<\/span>src !=<\/span> NULL<\/span>)<\/span>;<\/span>
      \nassert<\/span>(<\/span>(<\/span>src >=<\/span> usRegHoldingBuf)<\/span> &&<\/span>
      \n(<\/span>src +<\/span> size\/<\/span>2<\/span> <=<\/span> usRegHoldingBuf +<\/span> MAX_REGISTERS)<\/span>)<\/span>;<\/span><\/p>\n

      memcpy<\/span>(<\/span>dest,<\/span> src,<\/span> size)<\/span>;<\/span>
      \n}<\/span><\/p>\n

      3. \u6700\u7ec8\u7ed3\u8bba<\/h4>\n

      \u5728\u60a8\u7684\u4ee3\u7801\u4e2d：<\/p>\n

      memcpy<\/span>(<\/span>&<\/span>resistance,<\/span> &<\/span>usRegHoldingBuf[<\/span>res_reg]<\/span>,<\/span> 4<\/span>)<\/span>;<\/span><\/p>\n

      \u8fd9\u662f\u6b63\u786e\u7528\u6cd5，\u524d\u63d0\u662f：<\/p>\n

    • resistance \u662f uint32_t \u6216\u5176\u5b834\u5b57\u8282\u7c7b\u578b\u7684\u53d8\u91cf<\/li>\n
    • res_reg \u5728\u5bc4\u5b58\u5668\u6570\u7ec4\u7684\u6709\u6548\u8303\u56f4\u5185<\/li>\n

      \u800c：<\/p>\n

      memcpy<\/span>(<\/span>resistance,<\/span> &<\/span>usRegHoldingBuf[<\/span>res_reg]<\/span>,<\/span> 4<\/span>)<\/span>;<\/span><\/p>\n

      \u8fd9\u9700\u8981：<\/p>\n

    • resistance \u662f\u6307\u5411\u8db3\u591f\u5185\u5b58\u7684\u6307\u9488<\/li>\n
    • \u6307\u9488\u5df2\u6b63\u786e\u521d\u59cb\u5316（\u5982 resistance = malloc(4);）<\/li>\n

      \u5173\u952e\u8bb0\u5fc6\u70b9：
      \n&resistance \u2192 \u6211\u8981\u4fee\u6539resistance\u53d8\u91cf\u672c\u8eab
      \nresistance \u2192 \u6211\u8981\u4fee\u6539resistance\u6307\u5411\u7684\u5185\u5bb9
      \n\u9009\u9519\u76ee\u6807\u5730\u5740\u4f1a\u5bfc\u81f4\u4e25\u91cd\u5185\u5b58\u9519\u8bef！<\/p>\n","protected":false},"excerpt":{"rendered":"

      memcpy\u6df1\u5ea6\u89e3\u6790：&resistance vs resistance \u5173\u952e\u533a\u522b
      \n\u4e00\u3001\u672c\u8d28\u533a\u522b：\u76ee\u6807\u5730\u5740\u7684\u4e0d\u540c\u542b\u4e49
      \n1. \u5185\u5b58\u64cd\u4f5c\u793a\u610f\u56fe
      \ngraph LR
      \nS[\u6e90\u6570\u636e] –>|memcpy| D[\u76ee\u6807\u5730\u5740]
      \nsubgraph \u573a\u666f1：memcpy(&resistance, \u2026)
      \nA[resistance\u53d8\u91cf] –>|&resistance \u53d6\u5730\u5740| D1[\u53d8\u91cf\u5185\u5b58\u4f4d\u7f6e]
      \nend
      \nsubgraph \u573a\u666f2：memcp<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[99,43,78],"topic":[],"class_list":["post-72459","post","type-post","status-publish","format-standard","hentry","category-server","tag-java","tag-43","tag-78"],"yoast_head":"\nmemcpy\u6df1\u5ea6\u89e3\u6790\uff1a`&resistance` vs `resistance` \u5173\u952e\u533a\u522b - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.wsisp.com\/helps\/72459.html\" \/>\n<meta property=\"og:locale\" content=\"zh_CN\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"memcpy\u6df1\u5ea6\u89e3\u6790\uff1a`&resistance` vs `resistance` \u5173\u952e\u533a\u522b - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3\" \/>\n<meta property=\"og:description\" content=\"memcpy\u6df1\u5ea6\u89e3\u6790：&resistance vs resistance \u5173\u952e\u533a\u522b \u4e00\u3001\u672c\u8d28\u533a\u522b：\u76ee\u6807\u5730\u5740\u7684\u4e0d\u540c\u542b\u4e49 1. \u5185\u5b58\u64cd\u4f5c\u793a\u610f\u56fe graph LR S[\u6e90\u6570\u636e] -->|memcpy| D[\u76ee\u6807\u5730\u5740] subgraph \u573a\u666f1：memcpy(&resistance, \u2026) A[resistance\u53d8\u91cf] -->|&resistance \u53d6\u5730\u5740| D1[\u53d8\u91cf\u5185\u5b58\u4f4d\u7f6e] end subgraph \u573a\u666f2：memcp\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.wsisp.com\/helps\/72459.html\" \/>\n<meta property=\"og:site_name\" content=\"\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3\" \/>\n<meta property=\"article:published_time\" content=\"2026-02-05T10:05:22+00:00\" \/>\n<meta name=\"author\" content=\"admin\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"\u4f5c\u8005\" \/>\n\t<meta name=\"twitter:data1\" content=\"admin\" \/>\n\t<meta name=\"twitter:label2\" content=\"\u9884\u8ba1\u9605\u8bfb\u65f6\u95f4\" \/>\n\t<meta name=\"twitter:data2\" content=\"10 \u5206\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.wsisp.com\/helps\/72459.html\",\"url\":\"https:\/\/www.wsisp.com\/helps\/72459.html\",\"name\":\"memcpy\u6df1\u5ea6\u89e3\u6790\uff1a`&resistance` vs `resistance` \u5173\u952e\u533a\u522b - 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