added helper functions unavailable in vxWorks

asprintf.c

@@ -0,0 +1,34 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include "asprintf.h"
+
+int vasprintf(char** pbuffer, const char* format, va_list ap)
+{
+    va_list ap2;
+    int len;
+    FILE* f;
+    
+    /* print to null device to get required buffer length */
+    f = fopen("/null","w");
+    if (f == NULL) return -1;
+    __va_copy(ap2, ap);
+    len = vfprintf(f, format, ap2);
+    va_end(ap2);
+    fclose(f);
+    if (len < 0) return len;
+
+    *pbuffer = malloc(len+1);
+    if (*pbuffer == NULL) return -1;
+    return vsprintf(*pbuffer, format, ap);
+}
+
+int asprintf(char** pbuffer, const char* format, ...)
+{
+    va_list ap;
+    int len;
+
+    va_start(ap, format);
+    len = vasprintf(pbuffer, format, ap);
+    va_end(ap);
+    return len;
+}