c++ - OpenGL code Works in Windows but not Mac -

my school uses windows computers have mac @ home. code runs fine in windows reason errors running in xcode. wasn't sure frameworks include added glkit, cocoa, glut, , opengl. missing something?? xcode setup can work on homework same code work on windows. here code

#include <stdio.h> #include <stdarg.h> #include <math.h> #define gl_glext_prototypes #ifdef __apple__     #include <glut/glut.h> #else     #include <gl/glut.h> #endif  #define glut_key_escape 27  const glsizei windowwidth = 500; const glsizei windowheight = 500;  glfloat cuberotatex = 45.0f; glfloat cuberotatey = 45.0f; bool keys[255];  glvoid establishprojectionmatrix(glsizei width, glsizei height) {     glviewport(0, 0, width, height);      glmatrixmode(gl_projection);      glloadidentity();      gluperspective(45.0f, (glfloat)width / (glfloat)height, 0.1f, 200.0f); }  glvoid initgl(glsizei width, glsizei height) {     establishprojectionmatrix(width, height);      glshademodel(gl_smooth);      glclearcolor(0.0f, 0.0f, 0.0f, 1.0f);      glenable(gl_depth_test);     gldepthfunc(gl_lequal);      glhint(gl_perspective_correction_hint, gl_nicest);     glenable(gl_perspective_correction_hint); }  glvoid displayfps(glvoid) {     static long lasttime = glutget(glut_elapsed_time);     static int loops = 0;     static glfloat fps = 0.0f;      int newtime = glutget(glut_elapsed_time);      if (newtime - lasttime > 100)     {         float newfps = (float)loops / float(newtime - lasttime) * 1000.0f;         fps = (fps + newfps) / 2.0f;          char title[80];         sprintf_s(title, "opengl demo - %.2f", fps);         glutsetwindowtitle(title);          lasttime = newtime;         loops = 0;     }     loops++; }  glvoid drawscene(glvoid) {     glclear(gl_color_buffer_bit | gl_depth_buffer_bit);      glmatrixmode(gl_modelview);     glloadidentity();      gltranslatef(0, 0, -5.0f);     glrotatef(cuberotatex, 1.0, 0.0, 0.0);     glrotatef(cuberotatey, 0.0, 1.0, 0.0);      glbegin(gl_quads);     glcolor3f(0.0f, 1.0f, 1.0f);     glvertex3f( 1.0f,  1.0f, -1.0f);     glvertex3f(-1.0f,  1.0f, -1.0f);     glvertex3f(-1.0f,  1.0f,  1.0f);     glvertex3f( 1.0f,  1.0f,  1.0f);      glcolor3f(0.0f, 1.0f, 0.0f);     glvertex3f( 1.0f, -1.0f, -1.0f);     glvertex3f(-1.0f, -1.0f, -1.0f);     glvertex3f(-1.0f, -1.0f,  1.0f);     glvertex3f( 1.0f, -1.0f,  1.0f);      glcolor3f(1.0f, 0.0f, 0.0f);     glvertex3f( 1.0f,  1.0f, 1.0f);     glvertex3f(-1.0f,  1.0f, 1.0f);     glvertex3f(-1.0f, -1.0f, 1.0f);     glvertex3f( 1.0f, -1.0f, 1.0f);      glcolor3f(1.0f, 1.0f, 0.0f);     glvertex3f( 1.0f,  1.0f, -1.0f);     glvertex3f(-1.0f,  1.0f, -1.0f);     glvertex3f(-1.0f, -1.0f, -1.0f);     glvertex3f( 1.0f, -1.0f, -1.0f);      glcolor3f(0.0f, 0.0f, 1.0f);     glvertex3f(-1.0f,  1.0f,  1.0f);     glvertex3f(-1.0f,  1.0f, -1.0f);     glvertex3f(-1.0f, -1.0f, -1.0f);     glvertex3f(-1.0f, -1.0f,  1.0f);      glcolor3f(1.0f, 0.0f, 1.0f);     glvertex3f( 1.0f,  1.0f,  1.0f);     glvertex3f( 1.0f,  1.0f, -1.0f);     glvertex3f( 1.0f, -1.0f, -1.0f);     glvertex3f( 1.0f, -1.0f,  1.0f);     glend();      glflush();      glutswapbuffers();      displayfps(); } glboolean checkkeys(glvoid) {     const glfloat speed = 1.0f;      if ( keys[glut_key_escape] )         return true;      if (keys[glut_key_left])         cuberotatey -= speed;     if (keys[glut_key_right])         cuberotatey += speed;     if (keys[glut_key_up])         cuberotatex -= speed;     if (keys[glut_key_down])         cuberotatex += speed;      return false; } glvoid timerloop(int value) {     if (checkkeys())         exit(0);     glutpostredisplay();      gluttimerfunc(1, timerloop, 0); }    glvoid keyboardcb(unsigned char key, int x, int y) {     keys[key] = true; } glvoid keyboardupcb(unsigned char key, int x, int y) {     keys[key] = false; } glvoid keyboardspecialcb(int key, int x, int y) {     keys[key] = true; } glvoid keyboardspecialupcb(int key, int x, int y) {     keys[key] = false; }     int main(int argc, char** argv) {     glutinit(&argc, argv);      glutinitdisplaymode(glut_double);      int windowid = glutcreatewindow("opengl cube demo");     glutreshapewindow(windowwidth, windowheight);      initgl(windowwidth, windowheight);      glutdisplayfunc(drawscene);      glutkeyboardfunc(keyboardcb);     glutkeyboardupfunc(keyboardupcb);     glutspecialfunc(keyboardspecialcb);     glutspecialupfunc(keyboardspecialupcb);      gluttimerfunc(1, timerloop, 0);      glutmainloop();     return 0;  } 

why work in visual studio , not in xcode??

the errors compiler seem pretty clear. superficial reason doesn't work because code contains windows-isms not portable.

• c++ doesn't allow typedef of void indicate empty parameter list. have use void itself. so, changed glvoids voids.

• sprintf_s() windows-specific function. can replace snprintf(), have add parameter after buffer size of buffer. so, replace this:

  sprintf_s(title, ...); 

  with:

  snprintf(title, sizeof(title), ...); 

• the exit() function available cross-platform, have include right header. add #include <stdlib.h> near top of file.