gdImageXbmCtx    2696 ext/gd/gd.c    	_php_image_output_ctx(INTERNAL_FUNCTION_PARAM_PASSTHRU, PHP_GDIMG_TYPE_XBM, "XBM", gdImageXbmCtx);
gdImageXbmCtx     403 ext/gd/libgd/gd.h void gdImageXbmCtx(gdImagePtr image, char* file_name, int fg, gdIOCtx * out);