-D选项从g ++命令行未正确扩展 [英] -D option is expanded incorrectly from g++ command line

问题描述

在C ++ CodeBlocks项目中，我将以下定义添加到项目设置，编译器设置，#define：

 
 _DEBUG 
 DATA_DIR = \/ media / Shared / SiX / Data \
 

这将生成以下g ++命令行：

 
 g ++ -Wall -g -fPIC -save-temps -D_DEBUG -DDATA_DIR = \/ media / Shared / SiX / Data\-I ../Includes -c /media/Shared/SiX/SiXConfiguration/PathManager.cpp -o obj / Debug / PathManager.o 
 

代码不编译：

 
 char * commonDataDir; 
 #ifdef DATA_DIR 
 commonDataDir = DATA_DIR; 
 #endif 
 
 
 
查看预处理器输出文件，我看到源代码行以这种方式扩展：
 
 commonDataDir = / media / Shared / SiX / Data; 
 
我期望：
 
 commonDataDir = / media / Shared / SiX / Data; 
 
相同的代码从Eclipse CDT正确编译：
 
 g ++ -D_DEBUG -DDATA_DIR = \/ media / Shared / SiX / Data \-I/ media / Shared / SiX（复制）/包含-O3 -Wall -c -fmessage-length = 0 -fPIC -ggdb-MMD -MP -MFPathManager.d-MTPathManager.d-oPathManager.o../PathManager.cpp
 
因此，相同的命令行参数由g ++处理器以不同的方式处理。如何解决这个问题？
解决方案
将引号引入宏是很棘手的，不是一个好主意。
 
尝试使用预处理器添加所需的引号。
  #define DO_QUOTE（X）#X 
＃定义QUOTE（X）DO_QUOTE（X）
 
 #ifndef DATA_DIR 
 #define DATA_DIR / tmp 
 #endif 
 
 char commonDataDir [] = QUOTE DATA_DIR）; 
  
 
In C++ CodeBlocks project I added the following definitions to the project settings, compiler settings, #define:
_DEBUG
DATA_DIR=\"/media/Shared/SiX/Data\"
This produces the following g++ command line:
g++ -Wall  -g -fPIC -save-temps -D_DEBUG -DDATA_DIR=\"/media/Shared/SiX/Data\"    -I../Includes  -c /media/Shared/SiX/SiXConfiguration/PathManager.cpp -o obj/Debug/PathManager.o
This code does not compile:
char* commonDataDir;
#ifdef DATA_DIR
commonDataDir = DATA_DIR;
#endif
Looking at preprocessor output file, I see that source code line is expanded in this way:
commonDataDir = /media/Shared/SiX/Data;
I expect:
commonDataDir = "/media/Shared/SiX/Data";
The same code is compiled correctly from Eclipse CDT:
g++ -D_DEBUG -DDATA_DIR=\"/media/Shared/SiX/Data\" -I"/media/Shared/SiX (copy)/Includes" -O3 -Wall -c -fmessage-length=0 -fPIC -ggdb -MMD -MP -MF"PathManager.d" -MT"PathManager.d" -o"PathManager.o" "../PathManager.cpp"
So, the same command line parameter is handled differently by g++ proprocessor. How can I fix this?
解决方案
Putting quotes on macros is tricky and not a good idea.

Try and use the pre-processor to add the required quotes.
#define DO_QUOTE(X)       #X
#define QUOTE(X)          DO_QUOTE(X)

#ifndef DATA_DIR
#define DATA_DIR       /tmp
#endif

char commonDataDir[] = QUOTE(DATA_DIR);


                        
这篇关于-D选项从g ++命令行未正确扩展的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！