无法将“bool”转换为“NEDElement*”

Question

在安装 Omnetpp 的过程中，在最后一步 "make" 中，我遇到了一个错误

**`cannot convert ‘bool’ to ‘NEDElement`**  
 in return  np->getErrors()->addError("", "unable to allocate work memory"); return false;}
Makefile:51: recipe for target '/home/shivanshu/Desktop/FinalProject/omnetpp-4.2.2/out/gcc-release/src/nedxml/ned2.tab.o' failed
make[2]: *** [/home/shivanshu/Desktop/FinalProject/omnetpp-4.2.2/out/gcc-release/src/nedxml/ned2.tab.o] Error 1
make[2]: Leaving directory '/home/shivanshu/Desktop/FinalProject/omnetpp-4.2.2/src/nedxml'
Makefile:96: recipe for target 'nedxml' failed
make[1]: *** [nedxml] Error 2
make[1]: Leaving directory '/home/shivanshu/Desktop/FinalProject/omnetpp-4.2.2'
Makefile:19: recipe for target 'allmodes' failed
make: *** [allmodes] Error 2

对应的函数如下，有时返回NEDElement * type，有时返回bool。

NEDElement *doParseNED2(NEDParser *p, const char *nedtext)
{
#if YYDEBUG != 0      /* #if added --VA */
    yydebug = YYDEBUGGING_ON;
#endif

    NONREENTRANT_NED_PARSER(p);

    // reset the lexer
    pos.co = 0;
    pos.li = 1;
    prevpos = pos;

    yyin = NULL;
    yyout = stderr; // not used anyway

    // alloc buffer
    struct yy_buffer_state *handle = yy_scan_string(nedtext);
    if (!handle)
        {np->getErrors()->addError("", "unable to allocate work memory"); return false;}

    // create parser state and NEDFileElement
    resetParserState();
    ps.nedfile = new NedFileElement();

    // store file name with slashes always, even on Windows -- neddoc relies on that
    ps.nedfile->setFilename(slashifyFilename(np->getFileName()).c_str());
    ps.nedfile->setVersion("2");

    // storing the start and end position of the whole file for the NedFileElement
    // NOTE: we cannot use storePos() because it strips off the leading spaces
    // and comments from the element.
    YYLTYPE pos = np->getSource()->getFullTextPos();
    NEDSourceRegion region;
    region.startLine = pos.first_line;
    region.startColumn = pos.first_column;
    region.endLine = pos.last_line;
    region.endColumn = pos.last_column;
    ps.nedfile->setSourceRegion(region);

    // store file comment
    storeFileComment(ps.nedfile);

    ps.propertyscope.push(ps.nedfile);

    globalps = ps; // remember this for error recovery

    if (np->getStoreSourceFlag())
        storeSourceCode(ps.nedfile, np->getSource()->getFullTextPos());

    // parse
    try
    {
        yyparse();
    }
    catch (NEDException& e)
    {
        yyerror((std::string("error during parsing: ")+e.what()).c_str());
        yy_delete_buffer(handle);
        return 0;
    }

    if (np->getErrors()->empty())
    {
        // more sanity checks
        if (ps.propertyscope.size()!=1 || ps.propertyscope.top()!=ps.nedfile)
            INTERNAL_ERROR0(NULL, "error during parsing: imbalanced propertyscope");
        if (!ps.blockscope.empty() || !ps.typescope.empty())
            INTERNAL_ERROR0(NULL, "error during parsing: imbalanced blockscope or typescope");
    }
    yy_delete_buffer(handle);

    return ps.nedfile;
}

我在网上搜索了一下，但我发现，你应该有最新的 gcc 版本，但我已经有 gcc 7.5 版了。

请帮忙。

Answer 1

问题是它试图将布尔值转换为指针。您可以强制转换它，但我建议改为执行其他失败案例所做的事情：将 return false; 更改为 return 0;（或者更好，但与其他 return nullptr; 略有不同）。

无法将“bool”转换为“NEDElement*”

Cannot convert ‘bool’ to ‘NEDElement*’

gcc

makefile

bison

omnet++