egl: Add xeglthreads

Signed-off-by: Chia-I Wu <[email protected]>

1 files changed, 766 insertions, 0 deletions

diff --git a/progs/egl/xeglthreads.c b/progs/egl/xeglthreads.c
new file mode 100644
index 00000000000..5cc856ab3f3
--- /dev/null
+++ b/progs/egl/xeglthreads.c
@@ -0,0 +1,766 @@
+/*
+ * Copyright (C) 2000  Brian Paul   All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Ported to EGL by Chia-I Wu <[email protected]>
+ */
+
+
+/*
+ * This program tests EGL thread safety.
+ * Command line options:
+ *  -p                       Open a display connection for each thread
+ *  -l                       Enable application-side locking
+ *  -n <num threads>         Number of threads to create (default is 2)
+ *  -display <display name>  Specify X display (default is $DISPLAY)
+ *  -t                       Use texture mapping
+ *
+ * Brian Paul  20 July 2000
+ */
+
+
+/*
+ * Notes:
+ * - Each thread gets its own EGL context.
+ *
+ * - The EGL contexts share texture objects.
+ *
+ * - When 't' is pressed to update the texture image, the window/thread which
+ *   has input focus is signalled to change the texture.  The other threads
+ *   should see the updated texture the next time they call glBindTexture.
+ */
+
+
+#if defined(PTHREADS)   /* defined by Mesa on Linux and other platforms */
+
+#include <assert.h>
+#include <X11/Xlib.h>
+#include <X11/Xutil.h>
+#include <GL/gl.h>
+#include <EGL/egl.h>
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <pthread.h>
+
+
+/*
+ * Each window/thread/context:
+ */
+struct winthread {
+   Display *Dpy;
+   int Index;
+   pthread_t Thread;
+   Window Win;
+   EGLDisplay Display;
+   EGLContext Context;
+   EGLSurface Surface;
+   float Angle;
+   int WinWidth, WinHeight;
+   GLboolean NewSize;
+   GLboolean Initialized;
+   GLboolean MakeNewTexture;
+};
+
+
+#define MAX_WINTHREADS 100
+static struct winthread WinThreads[MAX_WINTHREADS];
+static int NumWinThreads = 0;
+static volatile GLboolean ExitFlag = GL_FALSE;
+
+static GLboolean MultiDisplays = 0;
+static GLboolean Locking = 0;
+static GLboolean Texture = GL_FALSE;
+static GLuint TexObj = 12;
+static GLboolean Animate = GL_TRUE;
+
+static pthread_mutex_t Mutex;
+static pthread_cond_t CondVar;
+static pthread_mutex_t CondMutex;
+
+
+static void
+Error(const char *msg)
+{
+   fprintf(stderr, "Error: %s\n", msg);
+   exit(1);
+}
+
+
+static void
+signal_redraw(void)
+{
+   pthread_mutex_lock(&CondMutex);
+   pthread_cond_broadcast(&CondVar);
+   pthread_mutex_unlock(&CondMutex);
+}
+
+
+static void
+MakeNewTexture(struct winthread *wt)
+{
+#define TEX_SIZE 128
+   static float step = 0.0;
+   GLfloat image[TEX_SIZE][TEX_SIZE][4];
+   GLint width;
+   int i, j;
+
+   for (j = 0; j < TEX_SIZE; j++) {
+      for (i = 0; i < TEX_SIZE; i++) {
+         float dt = 5.0 * (j - 0.5 * TEX_SIZE) / TEX_SIZE;
+         float ds = 5.0 * (i - 0.5 * TEX_SIZE) / TEX_SIZE;
+         float r = dt * dt + ds * ds + step;
+         image[j][i][0] =
+         image[j][i][1] =
+         image[j][i][2] = 0.75 + 0.25 * cos(r);
+         image[j][i][3] = 1.0;
+      }
+   }
+
+   step += 0.5;
+
+   glBindTexture(GL_TEXTURE_2D, TexObj);
+
+   glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_WIDTH, &width);
+   if (width) {
+      assert(width == TEX_SIZE);
+      /* sub-tex replace */
+      glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, TEX_SIZE, TEX_SIZE,
+                   GL_RGBA, GL_FLOAT, image);
+   }
+   else {
+      /* create new */
+      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+
+      glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, TEX_SIZE, TEX_SIZE, 0,
+                   GL_RGBA, GL_FLOAT, image);
+   }
+}
+
+
+
+/* draw a colored cube */
+static void
+draw_object(void)
+{
+   glPushMatrix();
+   glScalef(0.75, 0.75, 0.75);
+
+   glColor3f(1, 0, 0);
+
+   if (Texture) {
+      glBindTexture(GL_TEXTURE_2D, TexObj);
+      glEnable(GL_TEXTURE_2D);
+   }
+   else {
+      glDisable(GL_TEXTURE_2D);
+   }
+
+   glBegin(GL_QUADS);
+
+   /* -X */
+   glColor3f(0, 1, 1);
+   glTexCoord2f(0, 0);  glVertex3f(-1, -1, -1);
+   glTexCoord2f(1, 0);  glVertex3f(-1,  1, -1);
+   glTexCoord2f(1, 1);  glVertex3f(-1,  1,  1);
+   glTexCoord2f(0, 1);  glVertex3f(-1, -1,  1);
+
+   /* +X */
+   glColor3f(1, 0, 0);
+   glTexCoord2f(0, 0);  glVertex3f(1, -1, -1);
+   glTexCoord2f(1, 0);  glVertex3f(1,  1, -1);
+   glTexCoord2f(1, 1);  glVertex3f(1,  1,  1);
+   glTexCoord2f(0, 1);  glVertex3f(1, -1,  1);
+
+   /* -Y */
+   glColor3f(1, 0, 1);
+   glTexCoord2f(0, 0);  glVertex3f(-1, -1, -1);
+   glTexCoord2f(1, 0);  glVertex3f( 1, -1, -1);
+   glTexCoord2f(1, 1);  glVertex3f( 1, -1,  1);
+   glTexCoord2f(0, 1);  glVertex3f(-1, -1,  1);
+
+   /* +Y */
+   glColor3f(0, 1, 0);
+   glTexCoord2f(0, 0);  glVertex3f(-1, 1, -1);
+   glTexCoord2f(1, 0);  glVertex3f( 1, 1, -1);
+   glTexCoord2f(1, 1);  glVertex3f( 1, 1,  1);
+   glTexCoord2f(0, 1);  glVertex3f(-1, 1,  1);
+
+   /* -Z */
+   glColor3f(1, 1, 0);
+   glTexCoord2f(0, 0);  glVertex3f(-1, -1, -1);
+   glTexCoord2f(1, 0);  glVertex3f( 1, -1, -1);
+   glTexCoord2f(1, 1);  glVertex3f( 1,  1, -1);
+   glTexCoord2f(0, 1);  glVertex3f(-1,  1, -1);
+
+   /* +Y */
+   glColor3f(0, 0, 1);
+   glTexCoord2f(0, 0);  glVertex3f(-1, -1, 1);
+   glTexCoord2f(1, 0);  glVertex3f( 1, -1, 1);
+   glTexCoord2f(1, 1);  glVertex3f( 1,  1, 1);
+   glTexCoord2f(0, 1);  glVertex3f(-1,  1, 1);
+
+   glEnd();
+
+   glPopMatrix();
+}
+
+
+/* signal resize of given window */
+static void
+resize(struct winthread *wt, int w, int h)
+{
+   wt->NewSize = GL_TRUE;
+   wt->WinWidth = w;
+   wt->WinHeight = h;
+   if (!Animate)
+      signal_redraw();
+}
+
+
+/*
+ * We have an instance of this for each thread.
+ */
+static void
+draw_loop(struct winthread *wt)
+{
+   while (!ExitFlag) {
+
+      if (Locking)
+         pthread_mutex_lock(&Mutex);
+
+      if (!wt->Initialized) {
+         eglMakeCurrent(wt->Display, wt->Surface, wt->Surface, wt->Context);
+         printf("xeglthreads: %d: GL_RENDERER = %s\n", wt->Index,
+                (char *) glGetString(GL_RENDERER));
+         if (Texture /*&& wt->Index == 0*/) {
+            MakeNewTexture(wt);
+         }
+         wt->Initialized = GL_TRUE;
+      }
+
+      if (Locking)
+         pthread_mutex_unlock(&Mutex);
+
+      glEnable(GL_DEPTH_TEST);
+
+      if (wt->NewSize) {
+         GLfloat w = (float) wt->WinWidth / (float) wt->WinHeight;
+         glViewport(0, 0, wt->WinWidth, wt->WinHeight);
+         glMatrixMode(GL_PROJECTION);
+         glLoadIdentity();
+         glFrustum(-w, w, -1.0, 1.0, 1.5, 10);
+         glMatrixMode(GL_MODELVIEW);
+         glLoadIdentity();
+         glTranslatef(0, 0, -2.5);
+         wt->NewSize = GL_FALSE;
+      }
+
+      if (wt->MakeNewTexture) {
+         MakeNewTexture(wt);
+         wt->MakeNewTexture = GL_FALSE;
+      }
+
+      glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+      glPushMatrix();
+         glRotatef(wt->Angle, 0, 1, 0);
+         glRotatef(wt->Angle, 1, 0, 0);
+         glScalef(0.7, 0.7, 0.7);
+         draw_object();
+      glPopMatrix();
+
+      if (Locking)
+         pthread_mutex_lock(&Mutex);
+
+      eglSwapBuffers(wt->Display, wt->Surface);
+
+      if (Locking)
+         pthread_mutex_unlock(&Mutex);
+
+      if (Animate) {
+         usleep(5000);
+      }
+      else {
+         /* wait for signal to draw */
+         pthread_mutex_lock(&CondMutex);
+         pthread_cond_wait(&CondVar, &CondMutex);
+         pthread_mutex_unlock(&CondMutex);
+      }
+      wt->Angle += 1.0;
+   }
+}
+
+
+static void
+keypress(XEvent *event, struct winthread *wt)
+{
+   char buf[100];
+   KeySym keySym;
+   XComposeStatus stat;
+
+   XLookupString(&event->xkey, buf, sizeof(buf), &keySym, &stat);
+
+   switch (keySym) {
+   case XK_Escape:
+      /* tell all threads to exit */
+      if (!Animate) {
+         signal_redraw();
+      }
+      ExitFlag = GL_TRUE;
+      /*printf("exit draw_loop %d\n", wt->Index);*/
+      return;
+   case XK_t:
+   case XK_T:
+      if (Texture) {
+         wt->MakeNewTexture = GL_TRUE;
+         if (!Animate)
+            signal_redraw();
+      }
+      break;
+   case XK_a:
+   case XK_A:
+      Animate = !Animate;
+      if (Animate)  /* yes, prev Animate state! */
+         signal_redraw();
+      break;
+   case XK_s:
+   case XK_S:
+      if (!Animate)
+         signal_redraw();
+      break;
+   default:
+      ; /* nop */
+   }
+}
+
+
+/*
+ * The main process thread runs this loop.
+ * Single display connection for all threads.
+ */
+static void
+event_loop(Display *dpy)
+{
+   XEvent event;
+   int i;
+
+   assert(!MultiDisplays);
+
+   while (!ExitFlag) {
+
+      if (Locking) {
+         while (1) {
+            int k;
+            pthread_mutex_lock(&Mutex);
+            k = XPending(dpy);
+            if (k) {
+               XNextEvent(dpy, &event);
+               pthread_mutex_unlock(&Mutex);
+               break;
+            }
+            pthread_mutex_unlock(&Mutex);
+            usleep(5000);
+         }
+      }
+      else {
+         XNextEvent(dpy, &event);
+      }
+
+      switch (event.type) {
+         case ConfigureNotify:
+            /* Find winthread for this event's window */
+            for (i = 0; i < NumWinThreads; i++) {
+               struct winthread *wt = &WinThreads[i];
+               if (event.xconfigure.window == wt->Win) {
+                  resize(wt, event.xconfigure.width,
+                         event.xconfigure.height);
+                  break;
+               }
+            }
+            break;
+         case KeyPress:
+            for (i = 0; i < NumWinThreads; i++) {
+               struct winthread *wt = &WinThreads[i];
+               if (event.xkey.window == wt->Win) {
+                  keypress(&event, wt);
+                  break;
+               }
+            }
+            break;
+         default:
+            /*no-op*/ ;
+      }
+   }
+}
+
+
+/*
+ * Separate display connection for each thread.
+ */
+static void
+event_loop_multi(void)
+{
+   XEvent event;
+   int w = 0;
+
+   assert(MultiDisplays);
+
+   while (!ExitFlag) {
+      struct winthread *wt = &WinThreads[w];
+      if (XPending(wt->Dpy)) {
+         XNextEvent(wt->Dpy, &event);
+         switch (event.type) {
+         case ConfigureNotify:
+            resize(wt, event.xconfigure.width, event.xconfigure.height);
+            break;
+         case KeyPress:
+            keypress(&event, wt);
+            break;
+         default:
+            ; /* nop */
+         }
+      }
+      w = (w + 1) % NumWinThreads;
+      usleep(5000);
+   }
+}
+
+
+
+/*
+ * we'll call this once for each thread, before the threads are created.
+ */
+static void
+create_window(struct winthread *wt, EGLContext shareCtx)
+{
+   Window win;
+   EGLContext ctx;
+   EGLSurface surf;
+   EGLint attribs[] = { EGL_RED_SIZE, 1,
+                        EGL_GREEN_SIZE, 1,
+                        EGL_BLUE_SIZE, 1,
+                        EGL_DEPTH_SIZE, 1,
+                        EGL_NONE };
+   EGLConfig config;
+   EGLint num_configs;
+   EGLint vid;
+   int scrnum;
+   XSetWindowAttributes attr;
+   unsigned long mask;
+   Window root;
+   XVisualInfo *visinfo, visTemplate;
+   int num_visuals;
+   int width = 160, height = 160;
+   int xpos = (wt->Index % 8) * (width + 10);
+   int ypos = (wt->Index / 8) * (width + 20);
+
+   scrnum = DefaultScreen(wt->Dpy);
+   root = RootWindow(wt->Dpy, scrnum);
+
+   if (!eglChooseConfig(wt->Display, attribs, &config, 1, &num_configs)) {
+      Error("Unable to choose an EGL config");
+   }
+
+   assert(config);
+   assert(num_configs > 0);
+
+   if (!eglGetConfigAttrib(wt->Display, config, EGL_NATIVE_VISUAL_ID, &vid)) {
+      Error("Unable to get visual id of EGL config\n");
+   }
+
+   visTemplate.visualid = vid;
+   visinfo = XGetVisualInfo(wt->Dpy, VisualIDMask,
+                        &visTemplate, &num_visuals);
+   if (!visinfo) {
+      Error("Unable to find RGB, Z, double-buffered visual");
+   }
+
+   /* window attributes */
+   attr.background_pixel = 0;
+   attr.border_pixel = 0;
+   attr.colormap = XCreateColormap(wt->Dpy, root, visinfo->visual, AllocNone);
+   attr.event_mask = StructureNotifyMask | ExposureMask | KeyPressMask;
+   mask = CWBackPixel | CWBorderPixel | CWColormap | CWEventMask;
+
+   win = XCreateWindow(wt->Dpy, root, xpos, ypos, width, height,
+                        0, visinfo->depth, InputOutput,
+                        visinfo->visual, mask, &attr);
+   if (!win) {
+      Error("Couldn't create window");
+   }
+
+   XFree(visinfo);
+
+   {
+      XSizeHints sizehints;
+      sizehints.x = xpos;
+      sizehints.y = ypos;
+      sizehints.width  = width;
+      sizehints.height = height;
+      sizehints.flags = USSize | USPosition;
+      XSetNormalHints(wt->Dpy, win, &sizehints);
+      XSetStandardProperties(wt->Dpy, win, "xeglthreads", "xeglthreads",
+                              None, (char **)NULL, 0, &sizehints);
+   }
+
+   eglBindAPI(EGL_OPENGL_API);
+
+   ctx = eglCreateContext(wt->Display, config, shareCtx, NULL);
+   if (!ctx) {
+      Error("Couldn't create EGL context");
+   }
+   surf = eglCreateWindowSurface(wt->Display, config, win, NULL);
+   if (!surf) {
+      Error("Couldn't create EGL surface");
+   }
+
+   XMapWindow(wt->Dpy, win);
+   XSync(wt->Dpy, 0);
+
+   /* save the info for this window/context */
+   wt->Win = win;
+   wt->Context = ctx;
+   wt->Surface = surf;
+   wt->Angle = 0.0;
+   wt->WinWidth = width;
+   wt->WinHeight = height;
+   wt->NewSize = GL_TRUE;
+}
+
+
+/*
+ * Called by pthread_create()
+ */
+static void *
+thread_function(void *p)
+{
+   struct winthread *wt = (struct winthread *) p;
+   draw_loop(wt);
+   return NULL;
+}
+
+
+/*
+ * called before exit to wait for all threads to finish
+ */
+static void
+clean_up(void)
+{
+   int i;
+
+   /* wait for threads to finish */
+   for (i = 0; i < NumWinThreads; i++) {
+      pthread_join(WinThreads[i].Thread, NULL);
+   }
+
+   for (i = 0; i < NumWinThreads; i++) {
+      eglDestroyContext(WinThreads[i].Dpy, WinThreads[i].Context);
+      XDestroyWindow(WinThreads[i].Dpy, WinThreads[i].Win);
+   }
+}
+
+
+static void
+usage(void)
+{
+   printf("xeglthreads: test of EGL/GL thread safety (any key = exit)\n");
+   printf("Usage:\n");
+   printf("  xeglthreads [options]\n");
+   printf("Options:\n");
+   printf("   -display DISPLAYNAME  Specify display string\n");
+   printf("   -n NUMTHREADS  Number of threads to create\n");
+   printf("   -p  Use a separate display connection for each thread\n");
+   printf("   -l  Use application-side locking\n");
+   printf("   -t  Enable texturing\n");
+   printf("Keyboard:\n");
+   printf("   Esc  Exit\n");
+   printf("   t    Change texture image (requires -t option)\n");
+   printf("   a    Toggle animation\n");
+   printf("   s    Step rotation (when not animating)\n");
+}
+
+
+int
+main(int argc, char *argv[])
+{
+   char *displayName = NULL;
+   int numThreads = 2;
+   Display *dpy = NULL;
+   EGLDisplay *egl_dpy = NULL;
+   int i;
+   Status threadStat;
+
+   if (argc == 1) {
+      usage();
+   }
+   else {
+      int i;
+      for (i = 1; i < argc; i++) {
+         if (strcmp(argv[i], "-display") == 0 && i + 1 < argc) {
+            displayName = argv[i + 1];
+            i++;
+         }
+         else if (strcmp(argv[i], "-p") == 0) {
+            MultiDisplays = 1;
+         }
+         else if (strcmp(argv[i], "-l") == 0) {
+            Locking = 1;
+         }
+         else if (strcmp(argv[i], "-t") == 0) {
+            Texture = 1;
+         }
+         else if (strcmp(argv[i], "-n") == 0 && i + 1 < argc) {
+            numThreads = atoi(argv[i + 1]);
+            if (numThreads < 1)
+               numThreads = 1;
+            else if (numThreads > MAX_WINTHREADS)
+               numThreads = MAX_WINTHREADS;
+            i++;
+         }
+         else {
+            usage();
+            exit(1);
+         }
+      }
+   }
+
+   if (Locking)
+      printf("xeglthreads: Using explicit locks around Xlib calls.\n");
+   else
+      printf("xeglthreads: No explict locking.\n");
+
+   if (MultiDisplays)
+      printf("xeglthreads: Per-thread display connections.\n");
+   else
+      printf("xeglthreads: Single display connection.\n");
+
+   /*
+    * VERY IMPORTANT: call XInitThreads() before any other Xlib functions.
+    */
+   if (!MultiDisplays) {
+       if (!Locking) {
+           threadStat = XInitThreads();
+           if (threadStat) {
+               printf("XInitThreads() returned %d (success)\n",
+                      (int) threadStat);
+           }
+           else {
+               printf("XInitThreads() returned 0 "
+                      "(failure- this program may fail)\n");
+           }
+       }
+
+      dpy = XOpenDisplay(displayName);
+      if (!dpy) {
+         fprintf(stderr, "Unable to open display %s\n",
+                 XDisplayName(displayName));
+         return -1;
+      }
+      egl_dpy = eglGetDisplay(dpy);
+      if (!egl_dpy) {
+         fprintf(stderr, "Unable to get EGL display\n");
+         XCloseDisplay(dpy);
+         return -1;
+      }
+      if (!eglInitialize(egl_dpy, NULL, NULL)) {
+          fprintf(stderr, "Unable to initialize EGL display\n");
+          return -1;
+      }
+   }
+
+   pthread_mutex_init(&Mutex, NULL);
+   pthread_mutex_init(&CondMutex, NULL);
+   pthread_cond_init(&CondVar, NULL);
+
+   printf("xeglthreads: creating windows\n");
+
+   NumWinThreads = numThreads;
+
+   /* Create the EGL windows and contexts */
+   for (i = 0; i < numThreads; i++) {
+      EGLContext share;
+
+      if (MultiDisplays) {
+         WinThreads[i].Dpy = XOpenDisplay(displayName);
+         assert(WinThreads[i].Dpy);
+         WinThreads[i].Display = eglGetDisplay(WinThreads[i].Dpy);
+         assert(eglInitialize(WinThreads[i].Display, NULL, NULL));
+      }
+      else {
+         WinThreads[i].Dpy = dpy;
+         WinThreads[i].Display = egl_dpy;
+      }
+      WinThreads[i].Index = i;
+      WinThreads[i].Initialized = GL_FALSE;
+
+      share = (Texture && i > 0) ? WinThreads[0].Context : 0;
+
+      create_window(&WinThreads[i], share);
+   }
+
+   printf("xeglthreads: creating threads\n");
+
+   /* Create the threads */
+   for (i = 0; i < numThreads; i++) {
+      pthread_create(&WinThreads[i].Thread, NULL, thread_function,
+                     (void*) &WinThreads[i]);
+      printf("xeglthreads: Created thread %p\n",
+              (void *) WinThreads[i].Thread);
+   }
+
+   if (MultiDisplays)
+      event_loop_multi();
+   else
+      event_loop(dpy);
+
+   clean_up();
+
+   if (MultiDisplays) {
+      for (i = 0; i < numThreads; i++) {
+          eglTerminate(WinThreads[i].Display);
+          XCloseDisplay(WinThreads[i].Dpy);
+      }
+   }
+   else {
+      eglTerminate(dpy);
+      XCloseDisplay(dpy);
+   }
+
+   return 0;
+}
+
+
+#else /* PTHREADS */
+
+
+#include <stdio.h>
+
+int
+main(int argc, char *argv[])
+{
+   printf("Sorry, this program wasn't compiled with PTHREADS defined.\n");
+   return 0;
+}
+
+
+#endif /* PTHREADS */