INFO: Formal Parameters Default to Type int

ID: Q51198

The information in this article applies to:

Microsoft C/C++ Compiler (CL.EXE), included with:
- Microsoft C for MS-DOS, versions 6.0, 6.0a, 6.0ax
- Microsoft C for OS/2, versions 6.0, 6.0a
- Microsoft C/C++ for MS-DOS, version 7.0
- Microsoft Visual C++ for Windows, 16-bit edition, versions 1.0, 1.5
- Microsoft Visual C++, 32-bit Editions, versions 1.0, 2.0, 4.0, 5.0

SUMMARY

In Microsoft C, a function declaration such as the following does not generate a compiler error even though the variable "voida" is not referenced:


   void main (voida)
   {
   }

NOTE: This is true only for the C compiler, not the C++ compiler.

MORE INFORMATION

The C and QuickC compilers do not generate an error because the variable "voida" defaults to a variable of type int. The compilers understand the above function definition because they recognize the "old style" of ANSI C declarations as well as the new. In general, the equivalents of the above code are as follows:


   Old Style                           New Style
   ---------                           ---------

   void function (voida)               void function (int voida)
   int voida; <- default if missing    {
   {                                   }
   }

Please refer to "The C Programming Language" by Brian Kernighan and Dennis Ritchie for a discussion on differences between old and new style with regards to function definition.

Additional query words: 8.00 8.00c 9.00

Keywords : kbCompiler kbVC100 kbVC150 kbVC200 kbVC400 kbVC500 kbVC600
Version : MS- DOS:6.0,6.00a,6.00ax,7.0;OS/2:6.0,6.00a;WIN3X:1.0,1.5;WINNT:1.0,2.0,4.0,5.0 ;
Platform :
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