# Screen('Gamma?') causes seg fault **URL:** \ **Category:** Uncategorized\ **Created:** [August 8, 2004, 4:07am UTC](https://psychtoolbox.discourse.group/t/screen-39-gamma-39-causes-seg-fault/744 "2004-08-08T04:07:54Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![Allen\_Ingling](https://avatars.discourse-cdn.com/v4/letter/a/a183cd/32.png) [@Allen\_Ingling](https://psychtoolbox.discourse.group/u/Allen_Ingling)\ **Post date:** [August 8, 2004, 4:07am UTC](https://psychtoolbox.discourse.group/t/screen-39-gamma-39-causes-seg-fault/744/1 "2004-08-08T04:07:54Z")
Did anybody get the function Screen('Gamma?') to work in Windows? On my test machines it invariably causes a segmentation fault (see screen dump below). ScreenTest and most demos run successfully. System 1: Pentium 4 2.8 GHz running Windows XP sp1, DirectX9.2b. ATI Rage128 PRO (AGP4X). MATLAB R13 and R14 with/without -nojvm. Psychtoolbox 2.5.4. System 2: Pentium 4 2.5 GHz running Windows XP sp1, DirectX9.2b, Dell Intel 82845G (on-board). MATLAB R13 and Psychtoolbox 2.5.4. Thanks for your help, Vincent --- from System 1 running R14 Warning: Function call SCREEN invokes inexact match V:\projects\vspc\PsychToolbox\_2.54\PsychBasic\Screen.dll. > \> In ltScreenInitialize at 31 In vs at 73 You are using a Multiscan 500PS The refresh rate is 60 Hz The resolution is 1280x1024 pixels. Latest calibration was done on 14-May-2001 02:42:31 A loadable gamma table is detected! ------------------------------------------------------------------------ Segmentation violation detected at Sat Aug 07 20:43:53 2004 ------------------------------------------------------------------------ Configuration: MATLAB Version: 7.0.0.19920 (R14) Operating System: Microsoft Windows XP Window System: Version 5.1 (Build 2600: Service Pack 1) Processor ID: x86 Family 15 Model 2 Stepping 5, GenuineIntel Virtual Machine: Java is not enabled Default Charset: ibm-5348\_P100-1997 Register State: EAX = 8b008a00 EBX = 00000000 ECX = 00cdc124 EDX = 7ffe0304 ESI = 8b008a00 EDI = 00cdc140 EBP = 00cdc138 ESP = 00cdc134 EIP = 78791d67 FLG = 00010286 Stack Trace: [0] libmx.dll:\_mxGetN(0x8b008a00, 0x00cdc6a4, 0x00cdc5b4, 0) + 7 bytes [1] Screen.dll:0x04569993(0x99009800, 0x9b009a00, 0x9d009c00, 0x9f009e00) [2] 0x97009600 This error was detected while a MEX-file was running. If the MEX-file is not an official MathWorks function, please examine its source code for errors. Please consult the External Interfaces Guide for information on debugging MEX-files. If it is an official MathWorks function, please follow these steps in reporting this problem to The MathWorks so that we have the best chance of correcting it: 1. Send this crash report to [segv@...](mailto:segv@...) for automated analysis. For your convenience, this information has been recorded in: C:\DOCUME~1\Vincent\LOCALS~1\Temp\matlab\_crash\_dump.212 2. Also, if the problem is reproducible, send the crash report to [support@...](mailto:support@...) along with: - A specific list of steps that will reproduce the problem - Any M, MEX, MDL or other files required to reproduce the problem - Any error messages displayed to the command window A technical support engineer will contact you with further information. Thank you for your assistance. Please save your workspace and restart MATLAB before continuing your work. Error in ==\> ltLoadCalibration at 48 [oldGammaTable,dacSize]=SCREEN(screen.windowPtr,'Gamma',round(newGamInv),8); Error in ==\> vs at 74 ltLoadCalibration(myscreen,3); -- Vincent Bonin - [vincent@...](mailto:vincent@...) Smith-Kettlewell Eye Research 2318 Fillmore St. - San Francisco, CA 94115 Phone: +1 415 345 2155 - Fax: +1 415 345 8455