FIX: Truncated String from #pragma comment(exestr

• The Microsoft C/C++ Compiler (CL.EXE) included with: - Microsoft C/C++ for MS-DOS, version 7.0 - Microsoft Visual C++ for Windows, versions 1.0, 1.5 - Microsoft Visual C++ 32-bit Edition, versions 1.0, 2.0

SYMPTOMS

When you use "#pragma comment(exestr, <string>)" to place a text string, <string>, into an executable module, the entire string is sometimes not included.

CAUSE

Using Microsoft C/C++ version 7.0, Visual C++ for Windows, or Visual C++ 32- bit versions 1.0 and 2.x, the problem occurs when an attempt is made to embed a carriage-return (0x0D) or line-feed (0x0A) character somewhere other than at the end of the string.

RESOLUTION

A compiler specific workaround exists for this problem. For Microsoft C/C++ version 7.0, Visual C++ for Windows, or Visual C++ 32-bit versions 1.0 and 2.x, place each carriage-return or line-feed character at the end of the string.

The sample code in the MORE INFORMATION section below, demonstrates two other methods to work around this problem. The first method is to declare a character array in the application that contains the string to embed in the file. This method places the string into the application's data segment. The second method is similar to the first except that the compiler places the string into the application's code segment, and therefore it does not consume space in the data segment. Either of these methods loads the string into memory when the application runs.

A fourth method is available to applications developed for the Microsoft Windows operating system. Place the string into a STRINGTABLE resource. If you want, you can specify the LOADONCALL attribute so that the string is not loaded into memory until the application requires it.

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. This bug was corrected in Visual C++ version 4.0.

MORE INFORMATION

The #pragma comment(exestr, <string>) statement directs the compiler to place <string> into the object file. The linker places the string into the executable file. You can find the string by using an application that searches executable files for strings. However, the loader does not load the string into memory. You can use comment strings to store a version number or similar information in your executable file.

You can use the following sample code to demonstrate the problem:

Sample Code

   /* Compile options needed: none
   */

      #define __CR_LF__ "\x0d\x0a"
   /*
    * With Microsoft C/C++ version 7.0, Visual C++ for Windows,
    * or Visual C++ 32-bit versions 1.0 and 2.x, the first two
    * #pragma commented strings are placed in the executable,
    * the third is not.
    */

   #pragma comment(exestr, "This Comment EXESTR is OK" __CR_LF__)
   #pragma comment(exestr, "****************")
   #pragma comment(exestr, __CR_LF__ "This Comment EXESTR is NOT")

   /*
    * Other methods
    * char data_exestr[] = "\r\nData EXESTR";
    * char __based(__segname("_CODE"))code_exestr[] = "\r\nCode EXESTR";
    */

   void main()
   {
   }

REFERENCES

For information on a problem that the linker has with #pragma comment, please see the following article in the Microsoft Knowledge Base:

   ARTICLE-ID: Q102700
   TITLE     : No String in EXE from #pragma Comment(exestr, <string>)