splint命令: splint null.c

　　结果输出:

Splint 3.1.2--- 03 May 2009
Spec filenot found: null.lcl
null.c:2:65:Comment starts inside comment
A commentopen sequence (/*) appears within a comment. This usually means an
earliercomment was not closed. (Use -nestcomment to inhibit warning)
null.c: (infunction firstChar1)
null.c:4:10:Dereference of possibly null pointer s: *s
A possiblynull pointer is dereferenced. Value is either the result of a
functionwhich may return null (in which case， code should check it is not
null)， ora global， parameter or structure field declared with the null
qualifier.(Use -nullderef to inhibit warning)
null.c:3:33:Storage s may become null
Finishedchecking --- 2 code warnings

　　函数firstChar1和firstChar2都使用了null的说明，表示指针s可能是一个空指针，所以splint会对s的值使用情况进行检查，由于firstChar2中对s的值进行了判断，所以没有对firstChar2函数中s输出警告信息。

　　未定义变量错误:C中使用没有定义变量会出错，/*@in@*/说明的变量表示必须先进行定义./*@out*@/表明在执行过函数后，这个变量进行了定义。--个人感觉/*@out*@/类似与C#中的out关键字。

　　实例1:usedef.c

/*Program:usedef.c -- use splint check the varible undefined error or warnings */
//out represent varible *x will be defined after execution of function
extern void setVal(/*@out@*/int *x);
//in represent varible *x has been defined before the execution.
extern int getVal(/*@in@*/ int *x);
extern int mysteryVal(int *x);
int dumbfunc(/*@out@*/int *x，int i){
 if(i>3) return *x;
 else if(i>1)
  return getVal(x);
 else if(i==0)
  return mysteryVal(x);
 else{
  setVal(x);
  return *x;
 }
}

　　splint命令:splint usedef.c

　　splint执行的结果:

Splint 3.1.2--- 03 May 2009
usedef.c:(in function dumbfunc)
usedef.c:8:17:Value *x used before definition
#在一些执行路径中一个右值的被使用的时候可能没被初始化，
An rvalueis used that may not be initialized to a value on some executionpath. (Use-usedef to inhibit warning)
usedef.c:10:17:Passed storage x not completely defined (*x is undefined):
getVal(x)
Storagederivable from a parameter， return value or global is not defined.
Use/*@out@*/ to denote passed or returned storage which need not bedefined.
(Use-compdef to inhibit warning)
usedef.c:12:21:Passed storage x not completely defined (*x is undefined):
mysteryVal(x)
Finishedchecking --- 3 code warnings

　　错误原因:由于程序中没有对X定义，所以报出未定义的错误.但是由于setVal()使用了/*@out*@/说明，所以在语句“setVal(x)”和“returnx”中，没有报未定义错误。

　　类型错误:C语言中的变量类型比较多，彼此之间有些细微的差别，splint可以对变量的类型进行检查:

　　实例1.typeerr.c

/*Program: typeerr.c -- use splint to check type varible error */
int foo(int i，char *s，bool b1，bool b2){
 if(i=3) return b1;
 if(!i || s) return i;
 if(s) return 7;
 if(b1 == b2)
  return 3;
 return 2;
}