Hi Louis,
Thanks for the report. Yes, you are right, cmsCreateTransform
is not thread safe if the involved profiles are file-based. That is
because files are not locked when readed. Currently, only
cmsDoTransform() is thread safe, and strictly you have to
turn on USE_PTHREADS toggle on lcms.h
That is so because multithreading only make real sense when
applying rerendering. But your point is well taken, and locking the
file would be an interesting addition for next release, unfortunately
not for 1.17 since I am already out of schedule.
Thanks again.
Marti
----- Original Message -----
From: "Louis Solomon [SteelBytes]" <[EMAIL PROTECTED]>
To: "lcms-user" <lcms-user@lists.sourceforge.net>
Sent: Tuesday, June 05, 2007 8:13 AM
Subject: [Lcms-user] cmsCreateTransform is not thread safe
Hi,
cmsCreateTransform is not thread safe using 1.16 or 1.17b. Note, using
cmsCreate_sRGBProfile() instead of
cmsOpenProfileFromFile("AdobeRGB1998.icc","rb") does work, and so does
calling the two cmsCreateTransform()'s in succession. Test env: 32bit debug
target built with VS2005 on Vista64.
Louis Solomon
www.SteelBytes.com
#include <windows.h>
#include "lcms\lcms.h"
static cmsHPROFILE prof_xyz,prof_rgb;
static cmsHTRANSFORM trans_xyz_to_rgb,trans_rgb_to_xyz;
static DWORD WINAPI make_trans_xyz_to_rgb(LPVOID lpParameter)
{
trans_xyz_to_rgb = cmsCreateTransform(
prof_xyz,TYPE_XYZ_DBL,
prof_rgb,TYPE_RGB_DBL,
INTENT_ABSOLUTE_COLORIMETRIC,cmsFLAGS_NOTPRECALC);
return 0;
}
static DWORD WINAPI make_trans_rgb_to_xyz(LPVOID lpParameter)
{
trans_rgb_to_xyz = cmsCreateTransform(
prof_rgb,TYPE_RGB_DBL,
prof_xyz,TYPE_XYZ_DBL,
INTENT_ABSOLUTE_COLORIMETRIC,cmsFLAGS_NOTPRECALC);
return 0;
}
int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance,LPSTR
lpCmdLine,int nCmdShow)
{
prof_xyz = cmsCreateXYZProfile();
prof_rgb = cmsOpenProfileFromFile("AdobeRGB1998.icc","rb");
//cmsCreate_sRGBProfile();
for (int i=0;i<10;++i)
{
#define try_threads
#ifdef try_threads
DWORD threadid;
HANDLE workers[2];
workers[0] = CreateThread(NULL,0,make_trans_xyz_to_rgb,NULL,0,&threadid);
workers[1] = CreateThread(NULL,0,make_trans_rgb_to_xyz,NULL,0,&threadid);
WaitForMultipleObjects(2,workers,TRUE,INFINITE);
for (unsigned i=0;i<2;++i)
CloseHandle(workers[i]);
#else
make_trans_xyz_to_rgb(0);
make_trans_rgb_to_xyz(0);
#endif
cmsDeleteTransform(trans_xyz_to_rgb);
cmsDeleteTransform(trans_rgb_to_xyz);
}
cmsCloseProfile(prof_rgb);
cmsCloseProfile(prof_xyz);
}
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