Check for DISPLAY variable.

dacav · Jun 14, 2010 · 6136a5b · 6136a5b
1 parent e910969
commit 6136a5b
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Showing 3 changed files with 17 additions and 3 deletions.
diff --git a/src/gnup/pipe.hpp b/src/gnup/pipe.hpp
@@ -21,12 +21,14 @@ namespace gnup {
             void command (const char *fmt, ...);
 
         protected:
-            Comm (const char *prog) throw (CommError);
+            Comm (const char *prog, bool req_X) throw (CommError);
 
         private:
             pid_t child;
             FILE *output;
 
+            void checkX() throw (CommError);
+
     };
 
 }

diff --git a/src/gp_base.cpp b/src/gp_base.cpp
@@ -62,7 +62,7 @@ namespace gnup {
     }
 
     GnuPlot::GnuPlot (size_t dims, const char *prog) throw (CommError)
-           : Comm(prog)
+           : Comm(prog, true)
     {
         dimensions = dims;
     }

diff --git a/src/pipe.cpp b/src/pipe.cpp
@@ -10,10 +10,14 @@
 
 namespace gnup {
 
-    Comm::Comm (const char *prog) throw (CommError)
+    Comm::Comm (const char *prog, bool req_X) throw (CommError)
     {
         int pipefd[2];
 
+        if (req_X) {
+            checkX();
+        }
+
         if (pipe(pipefd) == -1) {
             CommError err("Unable to pipe");
             throw err;
@@ -42,6 +46,14 @@ namespace gnup {
         output = fdopen(pipefd[1], "a");
     }
 
+    void Comm::checkX () throw (CommError)
+    {
+        if (getenv("DISPLAY") == NULL) {
+            CommError err("Cannot find DISPLAY variable");
+            throw err;
+        }
+    }
+
     Comm::~Comm ()
     {
         fclose(output);