Q39145: QuickC Incorrectly Issues a C4051 Data Conversion Warning

Article: Q39145
Product(s): See article
Version(s): 1.00 1.01
Operating System(s): MS-DOS
Keyword(s): ENDUSER | | mspl13_c
Last Modified: 20-JAN-1989

The Microsoft Quick C Compiler generates a "C4051: data conversion"
warning message for the following code when compiled with warning
level 3. This occurs in the integrated environment QC as well as
the command line compiler, QCL.

The following is a code example:

void main()
{
  char temp ;
  temp = 0xff ;
}

The warning is noting that the variable "temp", which is a signed
char, is being initialized with a value that is larger than a signed
char can represent. The bit pattern is not affected in this example
since 0xff can be represented by an unsigned char.

This warning does not affect how the bits are stored in the byte
of storage.  The message is informing you that this bit pattern
will not be interpreted as expected in a signed character
translation.

This is expected behavior for the QuickC compiler Versions 1.00 and
1.01.

This warning is not produced in QuickC Version 2.00.

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