问题
I downloaded the source code and wanted to compile the file of scanner. It produces this error:
[meepo@localhost cs143-pp1]$ gcc -o lex.yy.o lex.yy.c -ll
In file included from scanner.l:15:0:
scanner.h:59:5: error: unknown type name ‘bool’
In file included from scanner.l:16:0:
utility.h:64:38: error: unknown type name ‘bool’
utility.h:74:1: error: unknown type name ‘bool’
In file included from scanner.l:17:0:
errors.h:16:18: fatal error: string: No such file or directory
compilation terminated.
And I tried to use different complier to compile it, but it appeared different errors.
[meepo@localhost cs143-pp1]$ g++ -o scan lex.yy.c -ll
/usr/bin/ld: cannot find -ll
collect2: ld returned 1 exit status
My os is 3.0-ARCH, I don't know why this happened. How do I fix the error?
回答1:
C90 does not support the boolean data type.
C99 does include it with this include:
#include <stdbool.h>
回答2:
C99 does, if you have
#include <stdbool.h>
If the compiler does not support C99, you can define it yourself:
// file : myboolean.h
#ifndef MYBOOLEAN_H
#define MYBOOLEAN_H
#define false 0
#define true 1
typedef int bool; // or #define bool int
#endif
(but note that this definition changes ABI for bool type so linking against external libraries which were compiled with properly defined bool may cause hard-to-diagnose runtime errors).
回答3:
Somewhere in your code there is a line #include <string>. This by itself tells you that the program is written in C++. So using g++ is better than gcc.
For the missing library: you should look around in the file system if you can find a file called libl.so. Use the locate command, try /usr/lib, /usr/local/lib, /opt/flex/lib, or use the brute-force find / | grep /libl.
Once you have found the file, you have to add the directory to the compiler command line, for example:
g++ -o scan lex.yy.c -L/opt/flex/lib -ll
回答4:
Just add the following:
#define __USE_C99_MATH
#include <stdbool.h>
来源：https://stackoverflow.com/questions/8133074/error-unknown-type-name-bool