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+====== How can a GAMS process communicate with another process? ======
+Sometimes, you want to exchange data between a running  GAMS process and some other process.  The following example
+shows how to do that.  Here a GAMS program and a C program continuously exchange data (a scalar).  The communication is done through ASCII and GDX files and the synchronization
+through some semaphores:
+<code>
+$Title Trivial example of two asynchronous processes
+(one is GAMS) that exchange data through ASCII files
+$onechoV > wait.cmd
+@echo off
+printf "--- Waiting for %1%done"
+:loop
+if exist %1%done goto finish
+printf "."
+sleep 5
+goto loop
+:finish
+printf "\n"
+rm -f %1%done
+$offecho
+$onechoV > read.gms
+Scalar Ccnt /
+$include Ccnt.txt
+/
+$offecho
+* C Program that reads data from GAMS and provides date for a running GAMS job
+$onechoV > gc.c
+#include
+void main() {
+  FILE *fp;
+  int  Gcnt=0;
+  printf("C - Program started\n");
+  while (Gcnt<10) {
+    system("wait.cmd G");           /* Wait for GAMS to write Gcnt.txt */
+    printf("--- Reading Gcnt.txt\n"); /* Read Gcnt.txt */
+    fp = fopen("Gcnt.txt","r");
+    fscanf(fp,"%d",&Gcnt);
+    fclose(fp);
+    Gcnt = 2*Gcnt;
+    printf("--- Writing Ccnt.txt (%d)\n", Gcnt); /* Write Ccnt.txt */
+    fp = fopen("Ccnt.txt","w");
+    fprintf(fp,"%d",Gcnt);
+    fclose(fp);
+    system("touch Cdone"); /* Tell the GAMS program we are done writing */
+  }
+  printf("C - Program terminated\n");
+}
+$offecho
+* Next line call your favorite C compiler
+* $call cl gc.c
+* Remove old semaphores
+$call rm -f Cdone Gdone
+* Start up the C Program (you can start this also from a different Window)
+$call start cmd /K gc.exe
+* The GAMS Process
+$eolcom //
+scalar cnt /3/;
+file fx / Gcnt.txt /;
+while (cnt < 10,
+  cnt=cnt - 1;
+  putclose fx cnt:0:0                       // write out the current scalar
+  execute 'touch Gdone';                    // Tell the C program GAMS writing is done
+  execute 'wait.cmd C';                     // wait for the C program to write out the updated scalar
+  execute 'gams read.gms gdx read.gdx lo=2' // From the ASCII file with the scalar create a GDX file
+  execute_load 'read', cnt=Ccnt;            // Load the updated scalar from the GDX file
+  display cnt;
+);
+* make sure the C program also gets to write out the current scalar
+putclose fx cnt:0:0
+execute 'touch Gdone';
+</code>

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