title: c )make error& link problem: i386:x86-64 architecture of input file, incompatible with i386 output
body: <p>I have this output with error message when i type "make" in terminal!!</p>
  
  <pre><code>gcc test1.o dispatchQueue.o -o test1 -pthread
  /usr/bin/ld: i386:x86-64 architecture of input file `test1.o' is incompatible with i386     output
  /usr/bin/ld: final link failed: Invalid operation
  collect2: ld returned 1 exit status
  make: *** [test1] Error 1
  </code></pre>
  
  <p>Is there anyone who can explain why and how to fix it? :(</p>
  
  <p>I'm attaching makefile just in case</p>
  
  <pre><code># Comment out the targets you don't want.
  
  # Runs all of the tests.
  all: test1 test2 test3 test4 test5 testFor
      ./test1
      ./test2
      ./test3
      ./test4
      ./test5
      ./testFor
  
  test1: test1.o dispatchQueue.o
      gcc test1.o dispatchQueue.o -o test1 -pthread
  
  test1.o: test1.c
      gcc -c test1.c
  
  test2: test2.o dispatchQueue.o
      gcc test2.o dispatchQueue.o -o test2 -pthread
  
  test2.o: test2.c
      gcc -c test2.c
  
  test3: test3.o dispatchQueue.o
      gcc test3.o dispatchQueue.o -o test3 -pthread
  
  test3.o: test3.c
      gcc -c test3.c
  
  test4: test4.o dispatchQueue.o
      gcc test4.o dispatchQueue.o -o test4 -pthread
  
  test4.o: test4.c
      gcc -c test4.c
  
  test5: test5.o dispatchQueue.o
      gcc test5.o dispatchQueue.o -o test5 -pthread
  
  test5.o: test5.c
      gcc -c test5.c
  
  testFor: testFor.o dispatchQueue.o
      gcc testFor.o dispatchQueue.o -o testFor -pthread
  
  testFor.o: testFor.c
      gcc -c testFor.c
  
  dispatchQueue.o: dispatchQueue.c dispatchQueue.h
      gcc -c dispatchQueue.c
  </code></pre>