我已经在Windows上使用虚拟框设置了ubuntu虚拟机。
我正在尝试运行C ++项目。生成文件如下所示：
CC = g++ -O2 -Wno-deprecated
tag = -i
ifdef linux
tag = -n
endif
test.out: Record.o Comparison.o ComparisonEngine.o Schema.o File.o DBFile.o y.tab.o lex.yy.o test.o
$(CC) -o test.out Record.o Comparison.o ComparisonEngine.o Schema.o File.o DBFile.o y.tab.o lex.yy.o test.o -lfl
main: Record.o Comparison.o ComparisonEngine.o Schema.o File.o y.tab.o lex.yy.o main.o
$(CC) -o main Record.o Comparison.o ComparisonEngine.o Schema.o File.o y.tab.o lex.yy.o main.o -lfl
test.o: test.cc
$(CC) -g -c test.cc
main.o: main.cc
$(CC) -g -c main.cc
Comparison.o: Comparison.cc
$(CC) -g -c Comparison.cc
ComparisonEngine.o: ComparisonEngine.cc
$(CC) -g -c ComparisonEngine.cc
DBFile.o: DBFile.cc
$(CC) -g -c DBFile.cc
File.o: File.cc
$(CC) -g -c File.cc
Record.o: Record.cc
$(CC) -g -c Record.cc
Schema.o: Schema.cc
$(CC) -g -c Schema.cc
y.tab.o: Parser.y
yacc -d Parser.y
sed $(tag) y.tab.c -e "s/ __attribute__ ((__unused__))$$/# ifndef __cplusplus\n __attribute__ ((__unused__));\n# endif/"
g++ -c y.tab.c
lex.yy.o: Lexer.l
lex Lexer.l
gcc -c lex.yy.c
clean:
rm -f *.o
rm -f *.out
rm -f y.tab.c
rm -f lex.yy.c
rm -f y.tab.h
运行make命令后，我会收到一堆警告
g++ -O2 -Wno-deprecated -g -c Record.cc
g++ -O2 -Wno-deprecated -g -c Comparison.cc
g++ -O2 -Wno-deprecated -g -c ComparisonEngine.cc
g++ -O2 -Wno-deprecated -g -c Schema.cc
Schema.cc: In constructor ‘Schema::Schema(const char*, const char*)’:
Schema.cc:46:9: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
fscanf (foo, "%s", space);
~~~~~~~^~~~~~~~~~~~~~~~~~
Schema.cc:58:10: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
fscanf (foo, "%s", space);
~~~~~~~^~~~~~~~~~~~~~~~~~
Schema.cc:84:9: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
fscanf (foo, "%s", space);
~~~~~~~^~~~~~~~~~~~~~~~~~
Schema.cc:91:10: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
fscanf (foo, "%s", space);
~~~~~~~^~~~~~~~~~~~~~~~~~
Schema.cc:95:11: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
fscanf (foo, "%s", space);
~~~~~~~^~~~~~~~~~~~~~~~~~
Schema.cc:106:10: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
fscanf (foo, "%s", space);
~~~~~~~^~~~~~~~~~~~~~~~~~
Schema.cc:114:10: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
fscanf (foo, "%s", space);
~~~~~~~^~~~~~~~~~~~~~~~~~
Schema.cc:118:10: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
fscanf (foo, "%s", space);
~~~~~~~^~~~~~~~~~~~~~~~~~
g++ -O2 -Wno-deprecated -g -c File.cc
File.cc: In member function ‘void File::GetPage(Page*, off_t)’:
File.cc:186:7: warning: ignoring return value of ‘ssize_t read(int, void*, size_t)’, declared with attribute warn_unused_result [-Wunused-result]
read (myFilDes, bits, PAGE_SIZE);
~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
File.cc: In member function ‘void File::AddPage(Page*, off_t)’:
File.cc:206:10: warning: ignoring return value of ‘ssize_t write(int, const void*, size_t)’, declared with attribute warn_unused_result [-Wunused-result]
write (myFilDes, &foo, sizeof (int));
~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
File.cc:223:8: warning: ignoring return value of ‘ssize_t write(int, const void*, size_t)’, declared with attribute warn_unused_result [-Wunused-result]
write (myFilDes, bits, PAGE_SIZE);
~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
File.cc: In member function ‘void File::Open(int, char*)’:
File.cc:258:8: warning: ignoring return value of ‘ssize_t read(int, void*, size_t)’, declared with attribute warn_unused_result [-Wunused-result]
read (myFilDes, &curLength, sizeof (off_t));
~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
File.cc: In member function ‘int File::Close()’:
File.cc:276:8: warning: ignoring return value of ‘ssize_t write(int, const void*, size_t)’, declared with attribute warn_unused_result [-Wunused-result]
write (myFilDes, &curLength, sizeof (off_t));
~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
g++ -O2 -Wno-deprecated -g -c DBFile.cc
yacc -d Parser.y
sed -i y.tab.c -e "s/ __attribute__ ((__unused__))$/# ifndef __cplusplus\n __attribute__ ((__unused__));\n# endif/"
g++ -c y.tab.c
y.tab.c: In function ‘int yyparse()’:
y.tab.c:1427:35: warning: ISO C++ forbids converting a string constant to ‘char*’ [-Wwrite-strings]
yyerror (YY_("syntax error"));
^
y.tab.c:1571:35: warning: ISO C++ forbids converting a string constant to ‘char*’ [-Wwrite-strings]
yyerror (YY_("memory exhausted"));
^
lex Lexer.l
gcc -c lex.yy.c
g++ -O2 -Wno-deprecated -g -c test.cc
g++ -O2 -Wno-deprecated -o test.out Record.o Comparison.o ComparisonEngine.o Schema.o File.o DBFile.o y.tab.o lex.yy.o test.o -lfl
除.o之外，所有文件均会编译生成各自的main.cc文件。所以我用这个命令编译它
g++ -O2 -Wno-deprecated -g -c -o main.o main.cc
现在main.o文件会编译并生成main.o
然后我使用./main.o运行它，并获得权限被拒绝
所以我用chmod 755 ./*摆脱了这个错误
现在运行main.o会出现此错误
bash: ./main.o cannot execute binary file Exec format error
通过研究，我发现此错误是由于架构和文件类型不匹配造成的。
file main.o输出 x86-64 和uname -m输出 x86_64
我无法找出问题所在。 任何帮助将不胜感激！谢谢！
答案 0 :(得分：3)
您正在尝试执行目标文件。 main.o之类的目标文件不可执行。它们仅包含组成可执行文件所需的部分代码。
您需要运行main（或者也许是test.out），它是实际的可执行文件。
权限警告告诉您同一件事（main.o不可执行），但是您用chmod覆盖了它。
main应该由make创建，如果使用make main或test.out（如果使用make或{{），则假定没有编译/链接错误1}}。链接器调用在Makefile的make test.out / main:目标中给出。如果test.out:生成编译器或链接器错误，则手动重复相同的命令将无法修复它。修正代码或Makefile。
还请注意，警告/错误在那里是有原因的。从C ++ 11开始，不允许将字符串文字转换为make，而只能转换为char*。在C ++ 03中已经不推荐使用。规避该规则只会在将来给您带来麻烦。修正您的代码，而不要添加const char*。