rem: RErrorString[0] = 0;
context: RConvertImage(RContext *context, RImage *image, Pixmap *pixmap){    RXImage *ximg=NULL;    assert(context!=NULL);    assert(image!=NULL);    assert(pixmap!=NULL);    /* clear error message */    RErrorString[0] = 0;    if (context->vclass == TrueColor)      ximg = image2TrueColor(context, image);    else if (context->vclass == PseudoColor || context->vclass == StaticColor)      ximg = image2PseudoColor(context, image);    else if (context->vclass == GrayScale || context->vclass == StaticGray)      ximg = image2GrayScale(context, image);    if (!ximg) {	strcat(RErrorString, ":could not convert RImage to XImage");#ifdef C_ALLOCA	alloca(0);#endif	return False;    }    *pixmap = XCreatePixmap(context->dpy, context->drawable, image->width,			    image->height, context->depth);    RPutXImage(context, *pixmap, context->copy_gc, ximg, 0, 0, 0, 0,	      image->width, image->height);    RDestroyXImage(context, ximg);#ifdef C_ALLOCA    alloca(0);#endif    return True;}