If more than one pixel is in error, the one that gets reported is arbitrary. XFreeColors can generate BadAccess , BadColor , and BadValue errors. Diagnostics BadAccess A client attempted to free a color map entry that it did not already allocate. BadAccess A client attempted to store into a read-only color map entry. BadColor A value for a Colormap argument does not name a defined Colormap.
Some numeric value falls outside the range of values accepted by the request.
Unless a specific range is specified for an argument, the full range defined by the argument's type is accepted. Any argument defined as a set of alternatives can generate this error.