www.digitalmars.com         C & C++   DMDScript  

c++.windows.32-bits - Error in wsprintf when using double as input

There is a bug in wsprintf when printing double values.    It appears to print
out the "f" or "lf"  of a "%4.0lf" rathern than the interpolated value.  I tried
several different formatting strings the same holds true for "%g".     

This was tested in the compiler version downloaded March 22-2005 with the
-DUNICODE=1 and -D_UNICODE=1 for the compiler running on Windows XP SP 2 fully

double dval = 10.0;
char *cb = new char[500];
TCHAR *wcb = new TCHAR[500];
sprintf(cb, "%2.0lf%%", dval);   
// 8 bit works
wsprintf(wcb, TEXT("%2.0lf%%"), dval);
// 16 bit fails and will only contain 
// the lf in the resulting string.

To work around this I hacked  a test where I converted the format picture to 8
bit string and then used the standard sprintf (8 bit char* string) rather than
the wsprintf (16 bit TCHAR*) and then converted the result back to 16 bit before
passing it to the windows function and it worked OK but these conversions are
not cheap so it would be nice to have it fixed.

My sample snippet

#ifdef MARS      
char *cb = new char[128];  
// buffer to hold 8 bit formated value
char *fmt= new char[128];  
// buffer to hold 8 bit format string.
memset(fmt, 0,128);

// convert format string from 16 bit to 8 bit.
int fmt_len = wcslen(fFormat);
int nc =  WideCharToMultiByte(CP_UTF8, 0, fFormat, fmt_len, fmt, 128, 0, 0);

// Generate 8 bit string representing fCurr_val
sprintf(cb, fmt, fCurr_val);

// Convert the 8 bit string back to 16 bit wide char.
int xw = MultiByteToWideChar(CP_UTF8, 0, cb, strlen(cb), tbuff, tbuff_size);

delete cb;
delete fmt;

wsprintf(tbuff, fFormat, fCurr_val);    

joe xdobs.com - If anybody out there is an expert in DLL usage with this
compiler then I could use some help.   I have code which generates a DLL and
libview utility claims everything is properly exported but when trying to use
the DLL by importing the lib still gets undefined symbols.   The DLL generated
by eVC works fine.
Mar 26 2005