对于包含安全字符串函数的Visual Studio版本,需要一个#define(以避免_CRT_SECURE_NO_DEPRECATE)

|| 不久前,我尝试使用Visual Studio 2010编译使用我在Visual Studio 2003中编写的库的MFC程序。毫不奇怪,我收到了一堆关于弃用和使用各种字符串函数的安全版本的警告。 然后,我更新了库中的相关功能以使用安全功能,并且编译良好。 后来,我尝试使用Visual Studio 2003在其他系统上再次对其进行编译,但对不存在的安全功能感到困惑。 我决定创建一种混合方法,该方法将允许我编译在两种环境中使用该库的程序,并在可用的情况下利用安全功能,如果没有,则将其别名为旧功能。 最初,我考虑过检查每个功能,以查看是否存在安全版本,但这无法正常工作,并且每个功能都需要单独工作:
#ifndef strcpy_s
    #define strcpy_s(a,b,c) strcpy(a,c)
#endif

#ifndef strcat_s
    #define strcat_s(a,b,c) strcat(a,c)
#endif

…
因此,我试图找出一种确定安全功能是否存在的方法。我知道它们是在Visual Studio 2005中引入的,但是是否有一个“ 1”或可以按以下方式使用的东西?
#ifndef SECURE_FUNCTIONS  // or #ifdef VS_VER_2005, #if (VS_VER >= 0x2005) etc.
    #define strcpy_s(a,b,c) strcpy(a,c)
    #define strcat_s(a,b,c) strcat(a,c)
    …
#endif
我检查了
crtdefs.h
,但发现没有任何用处。     
已邀请:
        我找到了解决方案;
_MSC_VER
宏/定义使这一过程变得简单。由于安全字符串函数是在Visual Studio 2005(VC ++版本
1400
)中添加的,因此只需执行以下操作:
#if _MSC_VER < 1400
    #define  _itoa_s(a,b,c)             _itoa(a,b,c)
    #define  wcscpy_s(a,b,c)            wcscpy(a,c)
    #define  _tprintf_s                 _tprintf
    #define  _sntprintf_s(a,b,c,d,...)  _sntprintf(a,c,d,...)
    …
#endif
现在,当代码在VS2005 +下进行编译时,它将具有更高的安全性;而在VS2003-上进行编译时,即使没有额外的安全性,仍然可以进行编译而无需修改。 这使移植和更新更加容易,因为即使您还不能使用VS2005 +进行编译,也可以更新库函数并在代码中使用安全字符串函数。这样,当您升级编译器时,无需对库或代码进行任何更改即可获得好处。它还使在旧版本和更新版本的Visual Studio上同时在同一代码库上进行工作变得更加容易(至少在某种程度上)。     
        Microsoft的某些安全功能是C ++ 11的一部分,因此现在应该可以移植。 安全功能与传统功能之间的重要区别是异常行为,有时还有返回值。许多程序员都不关注它们。这些差异通常被忽略。 例如,snprintf的异常行为与_snprintf_s不同:
snprintf
返回打印字符串所需的字符数,而不是                       无论终止缓冲区的大小如何,都要计算终止的空字符。                        我不认为snprintf本身会引发异常,但会导致无效的内存访问                       将。 如果buff足够大,则
_snprintf_s
将返回与snprintf相同的值,但是                        如果buff太小,或者buff或fmt是NULL指针,则_snprintf_s调用                        无效的参数处理程序,分别设置errno = ERANGE或EINVAL,                        并返回-1。     如果异常行为在旧代码中很重要,则从旧的传统函数转换为安全版本时请注意。 几年来,我一直在努力使用Microsoft \“ _ s \”的安全功能,特别是在编写为Visual Studio中的Windows平台和使用gcc / g ++的\'nix平台编译的代码时。重复使用旧的源代码时也很痛苦,因为要遍历代码将fprintf()更改为fprintf_s()等很麻烦。_CRT_SECURE_NO_DEPRICAT宏会禁止弃用警告,但我从来都不喜欢在不解决潜在问题的情况下关闭编译器警告;发出警告是有原因的。 我的临时补丁(我会不时承认,我仍然会用它)是一个包含宏的包含文件和一些内联函数,用于映射传统的安全函数。当然,映射不会模仿异常行为和返回值。如果需要,您也可以编写函数来模仿它,但是在某些时候,使用安全函数并更改旧代码以执行相同操作将变得更加容易。而且,某些安全功能不能容易地被映射,例如。 sprinf到sprintf_s。 这是我的包含文件(注释多于代码,但值得一读,恕我直言):
#pragma once
#if !defined(FCN_S_MACROS_H)
   #define   FCN_S_MACROS_H 

///////////////////////////////////////////////////////////////////////////////
//
// These macros provide (partial) compatibility of source code developed 
// for older MSVC versions and non-MSVC c++ compilers for some of Microsoft\'s
// security enhanced funcions, e.g. fscanf_s, sscanf_s, printf_s, strcpy_s,
// fopen_s.... Of course the standard functions still work in MSVS, but
// the choice is either to live with the annoying warning messages (bad idea)
// or set a compiler directive to stop the warnings (bad idea--there might
// important warnings as well as the annoying ones).
//
// It looks like a lot of the secure functions are now part of C++11. Those
// functions should be used in new code. The macros below can be used for
// for as a bridge for older code, but at some point it would be best to
// upgrade the code with the more secure functions. Eventually, the depricated
// functions may be removed, but probably not for a long time.
//
// Bill Brinson
// 21 February 2011 (updated once or twice since then).
//
///////////////////////////////////////////////////////////////////////////////
// Does It Work:
//
//    *** No warranty expresed nor implied. Use at your own risk. ***
//
// I\'ve tested most of the standard function to MS specific macros. They
// work in my codes so far, but Murphy says ...
//
// I usually write code in MSVS, using the standard functions, then port to
// linux if needed. I haven\'t though as much about the inverse macros,
// nor have I tested all of them. They seem unnecessary anyway. Too bad: they
// tend to be simpler.
// Test the macros yourself, and investigate exception behaviors before using
// them.
//
///////////////////////////////////////////////////////////////////////////////
//
// String Functions With No Count Parameter:
//
// The string functions that don\'t specify the maximum number of bytes to copy
// into the buffer (sprintf, strcpy, ...) are a problem. Using the sizeof()
// operator is a terrible idea (I should know--I though of it myself.
// Fortunately sanity prevailed before I used it in real code.
// In case you are tempted: the sizeof(buff) method WILL FAIL at runtime
// if buffer is not defined as an array (char cstring[32] or similar). For
// dynamically allocated memory, sizeof(ptr) returns the size of the pointer
// itself, not the allocated memory, so if your are copying no more than four
// bytes and you allocated at least that many, it would work due to blind luck.
// _memsize() (MS specific, but that\'s were it\'s needed) can be used for
// memory allocated with malloc, calloc, or realloc, but it doesn\'t work
// for char buff[size] or memory allocated with the new opperator. Does anyone
// still use malloc()?
// Overloaded functions taking char[] and *char to differentiate them might
// work for arrays and pointers to memory allocated by malloc et. al., but not
// for pointers to memory allocated by new (which have the same type, so not
// differentiated by the overloaded functions).
// If someone an idea, please let me know.
//
// This should only be an issue for legacy code; use snprintf, strncpy, etc.
// in new code (which you already do, right?), and make sure count has an
// appropriate value. For legacy code containing sprintf, strcpy, etc.,
// I\'ve decided to just bite the bullet: let the MS compiler point out the
// unsafe functions, then change them to the safer (but standard) versions
// that specify the allowable number of bytes to copy.
//
///////////////////////////////////////////////////////////////////////////////
// Exception Behavior:
//
// This is an important difference between the MS decreed safe functions and
// the traditional C/C++ functions.
// I suspect all of the MS specific functions have different exception behaviors.
// For example the exception behavior of snprintf is different from _snprintf_s:
//    snprintf returns the number of characters required to print the string, not
//    counting the terminating null character, regardless of the size of the buffer.
//    I don\'t think snprintf raises exceptions.
//    
//    _snprintf_s returns same value as snprintf if buff is sufficiently large, but
//    if buff is too small, or buff or fmt is a NULL pointer, _snprintf_s invokes the 
//    invalid parameter handler, sets errno = ERANGE or EINVAL, respectively,
//    and returns -1.
// If return values and exception behaviors are important in your code, create
// your own functions to handle the conversions.
//
///////////////////////////////////////////////////////////////////////////////
// Overloads:
//
// The macros below handle only the most common (for me, at least) overloads.
//
///////////////////////////////////////////////////////////////////////////////
// Suggetions:
//
// Yes please. There are a ton of these MS specific \"safe\" functions. I\'ve
// only done a few.
//
///////////////////////////////////////////////////////////////////////////////
// License:
//
// I suppose someone might care about this.
// Sure, use what you like, delete what you don\'t. Modify it to your hearts
// content.
// I wouldn\'t mind getting an attaboy or something if it works (not required).
// If it doesn\'t work, blame MS.
//
///////////////////////////////////////////////////////////////////////////////

// #include <cstdlib> // Do I need cstdlib? Hmm...maybe for sizeof()?
   #include <cstdio>
   #include <string> // Need this for _stricmp
   using namespace std;

   // _MSC_VER = 1400 is MSVC 2005. _MSC_VER = 1600 (MSVC 2010) was the current
   // value when I wrote (some of) these macros.
   #if (defined(_MSC_VER) && (_MSC_VER >= 1400) )

      // The function plus macro strategy could be used for most of the offending
      // MS functions, particularly for maintaining consistent exception behaviors
      // and return values. T
      // inline is for run time efficiency, but the compiler is not
      // constrained to comply.
      inline extern
      FILE*   fcnSMacro_fopen_s(char *fname, char *mode)
      {  FILE *fptr;
         fopen_s(&fptr, fname, mode);
         return fptr;
      }
      #define fopen(fname, mode)            fcnSMacro_fopen_s((fname), (mode))

      inline extern
      char* fcnSMacro_strtok_s(char *strng, char *delimiters)
      {  static char *cntx; // This static variable causes the same problem
                            // as the original strtok: can\'t alternate search
                            // strings in the same process (MS says \"thread\").
         if(strng != NULL) *cntx = NULL;
         char *cptr = strtok_s(strng, delimiters, &cntx);
         return cptr;
      }
      #define strtok(strng, delim)          fcnSMacro_strtok_s((strng), (delim))

      #define fcloseall()                   _fcloseall()

      // I substituded count+1 for snprintf\'s buffer size argument. For well
      // written code, the buffer size should be at least one more than count
      // to leave room for the terminating \'\\0\'.
      #define snprintf(buff, count, ...)    _snprintf_s((buff), (count+1), (count), __VA_ARGS__)

      #define printf(...)                   printf_s(__VA_ARGS__)
      #define fprintf(fptr, ...)            fprintf_s((fptr), __VA_ARGS__)

      // I don\'t have a solution for mapping sprinf to sprintf_s. There are other
      // functions like this.
//    #define sprintf                       ???
//    #define strcpy(s1, s2)                ???

      // These mappings look trivial, but the secure functions likely have different
      // exception behaviors and maybe different return values.
      #define fscanf                        fscanf_s
      #define sscanf                        sscanf_s
      #define scanf                         scanf_s                        

      // strcmpi is deprecated in VS 2015. Don\'t know about 2013 or 2014
      #define strcmpi                       _stricmp

      // No conversion needed for strncmp (yet). I guess MS hasn\'t gotten around
      // to it yet.
//    #define strncmp                       ???

      #define strncpy(dest, source, count)  strcpy_s((dest), (count), (source))
      #define strncat(dest, source, count)  strcat_s((dest), (count), (source))

   #else
      // I usually write code in MSVS, using the standard functions, then port to linux if needed.
      // I haven\'t though as much about the inverse macros, nor have I tested all of them.
      // Test them yourself and investigate exception behaviors before using them.

      #define fscanf_s                         fscanf
      #define sscanf_s                         sscanf
      #define scanf_s                          scanf
      #define printf_s                         printf
      #define sprintf_s                        snprintf
      #define fprintf_s                        fprintf
      #define strcpy_s(dest, count, source)    strncpy( (dest), (source), (count) )
      #define fopen_s(fp, fmt, mode)          *(fp)=fopen( (fmt), (mode))
      #define _fcloseall                       fcloseall
      #define strtok_s                         strtok
      #define _strcmpi                         strcmpi
   #endif //_MSC_VER
#endif // FCN_S_MACROS_H
    

要回复问题请先登录注册