Added OpenACC C main example

Makefile

@@ -8,10 +8,13 @@ FC=pgfortran
 FFLAGS=-fast -acc -ta=nvidia -Minfo=accel
 LDFLAGS=-Mcuda 
 
-EXES=cuda_main cuf_main cuf_openacc_main thrust
+EXES=cuda_main cuf_main cuf_openacc_main openacc_c_main thrust
 
 all: $(EXES)
 
+openacc_c_main: saxpy_cuda.o openacc_c_main.o
+	$(CC) -o $@ $(CFLAGS) $^ $(LDFLAGS)
+
 cuda_main: saxpy_openacc_c.o cuda_main.o
 	$(CC) -o $@ $(CFLAGS) $^ $(LDFLAGS)
 

openacc_c_main.c

@@ -0,0 +1,34 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+extern void saxpy(int,float,float*,float*);
+
+int main(int argc, char **argv)
+{
+  float *x, *y, tmp;
+  int n = 1<<20, i;
+
+  x = (float*)malloc(n*sizeof(float));
+  y = (float*)malloc(n*sizeof(float));
+
+  #pragma acc data create(x[0:n]) copyout(y[0:n])
+  {
+    #pragma acc kernels
+    {
+      for( i = 0; i < n; i++)
+      {
+        x[i] = 1.0f;
+        y[i] = 0.0f;
+      }
+    }
+
+    #pragma acc host_data use_device(x,y)
+    {
+      saxpy(n, 2.0, x, y);
+    }
+  }
+
+  fprintf(stdout, "y[0] = %f\n",y[0]);
+  return 0;
+}

saxpy_cuda.cu

@@ -0,0 +1,17 @@
+__global__
+void saxpy_kernel(int n, float a, float *x, float *y)
+{
+  int i = blockDim.x * blockIdx.x + threadIdx.x;
+
+  if ( i < n )
+    y[i] += a * x[i];
+}
+extern "C" void saxpy(int n ,float a, float *x, float *y)
+{
+  dim3 griddim, blockdim;
+
+  blockdim = dim3(128,1,1);
+  griddim = dim3(n/blockdim.x,1,1);
+
+  saxpy_kernel<<<griddim,blockdim>>>(n,a,x,y);
+}