在c++中编译Lex输出时出错

Error compiling Lex output in C++

本文关键字：输出 出错 Lex 编译 c++      更新时间：2023-10-16

当我将Lex的输出编译为c++时，我得到了这些错误:

$ make
[  6%] Building CXX object lib/CMakeFiles/lang.dir/lex_lexer.cpp.o
/home/michael/Projects/lang/build/lib/lex_lexer.cpp: In function ‘int lang::lexyacc::yylex()’:                                         
/home/michael/Projects/lang/build/lib/lex_lexer.cpp:789:1: warning: label ‘find_rule’ defined but not used
/home/michael/Projects/lang/build/lib/lex_lexer.cpp: In function ‘void lang::lexyacc::yypop_buffer_state()’:
/home/michael/Projects/lang/build/lib/lex_lexer.cpp:1542:37: error: call of overloaded ‘yy_delete_buffer(yy_buffer_state*)’ is ambiguous
/home/michael/Projects/lang/build/lib/lex_lexer.cpp:1427:10: note: candidates are: void lang::lexyacc::yy_delete_buffer(yy_buffer_state*)
/home/michael/Projects/lang/build/lib/lex_lexer.cpp:303:6: note:                 void yy_delete_buffer(yy_buffer_state*)
/home/michael/Projects/lang/build/lib/lex_lexer.cpp: In function ‘yy_buffer_state* lang::lexyacc::yy_scan_buffer(char*, yy_size_t)’:
/home/michael/Projects/lang/build/lib/lex_lexer.cpp:1629:25: error: call of overloaded ‘yy_switch_to_buffer(yy_buffer_state*&)’ is ambiguous
/home/michael/Projects/lang/build/lib/lex_lexer.cpp:1354:10: note: candidates are: void lang::lexyacc::yy_switch_to_buffer(yy_buffer_state*)
/home/michael/Projects/lang/build/lib/lex_lexer.cpp:301:6: note:                 void yy_switch_to_buffer(yy_buffer_state*)
/home/michael/Projects/lang/build/lib/lex_lexer.cpp: In function ‘int lang::lexyacc::yylex_destroy()’:
/home/michael/Projects/lang/build/lib/lex_lexer.cpp:1834:39: error: call of overloaded ‘yy_delete_buffer(yy_buffer_state*)’ is ambiguous
/home/michael/Projects/lang/build/lib/lex_lexer.cpp:1427:10: note: candidates are: void lang::lexyacc::yy_delete_buffer(yy_buffer_state*)
/home/michael/Projects/lang/build/lib/lex_lexer.cpp:303:6: note:                 void yy_delete_buffer(yy_buffer_state*)
/home/michael/Projects/lang/build/lib/lex_lexer.cpp: At global scope:
/home/michael/Projects/lang/build/lib/lex_lexer.cpp:308:13: warning: ‘void yyensure_buffer_stack()’ declared ‘static’ but never defined
/home/michael/Projects/lang/build/lib/lex_lexer.cpp:309:13: warning: ‘void yy_load_buffer_state()’ declared ‘static’ but never defined
/home/michael/Projects/lang/build/lib/lex_lexer.cpp:310:13: warning: ‘void yy_init_buffer(yy_buffer_state*, FILE*)’ declared ‘static’ but never defined
/home/michael/Projects/lang/build/lib/lex_lexer.cpp:361:22: warning: ‘yy_state_type yy_get_previous_state()’ declared ‘static’ but never defined
/home/michael/Projects/lang/build/lib/lex_lexer.cpp:362:22: warning: ‘yy_state_type yy_try_NUL_trans(yy_state_type)’ declared ‘static’ but never defined
/home/michael/Projects/lang/build/lib/lex_lexer.cpp:363:12: warning: ‘int yy_get_next_buffer()’ declared ‘static’ but never defined
/home/michael/Projects/lang/build/lib/lex_lexer.cpp:364:13: warning: ‘void yy_fatal_error(const char*)’ declared ‘static’ but never defined
/home/michael/Projects/lang/build/lib/lex_lexer.cpp:1212:17: warning: ‘void lang::lexyacc::yyunput(int, char*)’ defined but not used
/home/michael/Projects/lang/build/lib/lex_lexer.cpp:1867:12: warning: ‘int lang::lexyacc::yy_flex_strlen(const char*)’ defined but not used
/home/michael/Projects/lang/build/lib/lex_lexer.cpp:1162:26: warning: ‘yy_state_type lang::lexyacc::yy_get_previous_state()’ defined but not used
/home/michael/Projects/lang/build/lib/lex_lexer.cpp:1193:26: warning: ‘yy_state_type lang::lexyacc::yy_try_NUL_trans(yy_state_type)’ defined but not used
/home/michael/Projects/lang/build/lib/lex_lexer.cpp:1450:17: warning: ‘void lang::lexyacc::yy_init_buffer(yy_buffer_state*, FILE*)’ defined but not used
/home/michael/Projects/lang/build/lib/lex_lexer.cpp:1556:13: warning: ‘void lang::lexyacc::yyensure_buffer_stack()’ defined but not used
/home/michael/Projects/lang/build/lib/lex_lexer.cpp:1689:13: warning: ‘void lang::lexyacc::yy_fatal_error(const char*)’ defined but not used
make[2]: *** [lib/CMakeFiles/lang.dir/lex_lexer.cpp.o] Error 1
make[1]: *** [lib/CMakeFiles/lang.dir/all] Error 2
make: *** [all] Error 2

实际错误如下:

$ make 2>&1 | grep 'error:'
/home/michael/Projects/lang/build/lib/lex_lexer.cpp:1542:37: error: call of overloaded ‘yy_delete_buffer(yy_buffer_state*)’ is ambiguous
/home/michael/Projects/lang/build/lib/lex_lexer.cpp:1629:25: error: call of overloaded ‘yy_switch_to_buffer(yy_buffer_state*&)’ is ambiguous
/home/michael/Projects/lang/build/lib/lex_lexer.cpp:1834:39: error: call of overloaded ‘yy_delete_buffer(yy_buffer_state*)’ is ambiguous

但是我看了一下文件，没有不同签名的yy_delete_buffer的多个定义。

我该怎么办?

两个'候选'函数具有相同的签名，但位于不同的命名空间。

我所能猜到的是，在某种程度上有一些混乱的函数的前向定义放置(或未能放置)它在lang::lexyacc命名空间

嗯，这看起来像是一个奇怪的命名空间问题，你在两个不同的命名空间中有两个声明，例如

 lang::lexyacc::yy_delete_buffer(yy_buffer_state*)

和

 yy_delete_buffer(yy_buffer_state*)

它们有相同的参数列表，但它们驻留在不同的命名空间中，另一个在lang::lexyacc中，另一个在default中。

如果你找不到原因，你可以给出

 %option c++

选项来获得一个真正的c++扫描器类。

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