Example of an "extern" declaration to reuse a global variable defined in one file in another file.

Dependencies:   mbed

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API Documentation at this revision

Comitter:
bjo3rn
Date:
Wed Sep 23 20:45:28 2015 +0000
Commit message:
initial commit;

Changed in this revision

main.cpp Show annotated file Show diff for this revision Revisions of this file
mbed.bld Show annotated file Show diff for this revision Revisions of this file
myWait.cpp Show annotated file Show diff for this revision Revisions of this file
myWait.h Show annotated file Show diff for this revision Revisions of this file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Wed Sep 23 20:45:28 2015 +0000
@@ -0,0 +1,13 @@
+#include "mbed.h"
+#include "myWait.h"
+DigitalOut redLed(LED_RED);
+DigitalOut greenLed(LED_GREEN);
+
+int main() {
+    while(1) {
+        redLed = 1;
+        myWait(0.2);
+        redLed = 0;
+        myWait(0.2);
+    }
+}
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed.bld	Wed Sep 23 20:45:28 2015 +0000
@@ -0,0 +1,1 @@
+http://mbed.org/users/mbed_official/code/mbed/builds/4f6c30876dfa
\ No newline at end of file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/myWait.cpp	Wed Sep 23 20:45:28 2015 +0000
@@ -0,0 +1,12 @@
+#include "mbed.h"
+#include "myWait.h"
+
+// extern declares that the global variable greenLed is defined in a different source file
+extern DigitalOut greenLed;
+
+// definition of our custom wait function
+void myWait(float t) {
+    greenLed=0; //turn on
+    wait(t); //wait
+    greenLed=1; //turn off
+}
\ No newline at end of file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/myWait.h	Wed Sep 23 20:45:28 2015 +0000
@@ -0,0 +1,7 @@
+#ifndef MYWAIT_H
+#define MYWAIT_H
+
+//declare a custom wait function
+void myWait(float t);
+
+#endif
\ No newline at end of file