XtDisplayStringConversionWarning - issue a conversion warning message
#include <X11/Intrinsic.h>
void XtDisplayStringConversionWarning(Display* display,
    const char *from_value, const char *to_type);
  - display
- Specifies the display connection with which the conversion is
    associated.
- from_value
- Specifies the string that could not be converted.
- to_type
- Specifies the target representation type requested.
The XtDisplayStringConversionWarning function issues a warning message
  using XtAppWarningMsg with name “conversionError”, type
  “string”, class “XtToolkitError”, and the default
  message string “Cannot convert "from_value" to type
  to_type”.To issue other types of warning or error messages, the type
    converter should use XtAppWarningMsg or XtAppErrorMsg.
XtAppWarningMsg(3t)
X Toolkit Intrinsics - C Language Interface
Xlib - C Language X Interface