diff --git a/include/mxx/file.hpp b/include/mxx/file.hpp
index 8cce88b..49f6d62 100644
--- a/include/mxx/file.hpp
+++ b/include/mxx/file.hpp
@@ -105,7 +105,7 @@ struct file {
 
     void open(const std::string& filename, int mode) {
         this->filename = filename;
-        MPI_File_open(MPI_COMM_SELF, filename.c_str(), mode, MPI_INFO_NULL, &handle);
+        MPI_File_open(MPI_COMM_SELF, &filename[0], mode, MPI_INFO_NULL, &handle);
         this->isopen = true;
     }
 
@@ -122,7 +122,7 @@ struct file {
     }
 
     static void delete_file(const std::string& filename) {
-        MPI_File_delete(filename.c_str(), MPI_INFO_NULL);
+        MPI_File_delete(&filename[0], MPI_INFO_NULL);
     }