-PMEMblkpool *(*pmemblk_create) (const char *, size_t, size_t, mode_t) = NULL;
-PMEMblkpool *(*pmemblk_open) (const char *, size_t) = NULL;
-void (*pmemblk_close) (PMEMblkpool *) = NULL;
-size_t(*pmemblk_nblock) (PMEMblkpool *) = NULL;
-size_t(*pmemblk_bsize) (PMEMblkpool *) = NULL;
-int (*pmemblk_read) (PMEMblkpool *, void *, off_t) = NULL;
-int (*pmemblk_write) (PMEMblkpool *, const void *, off_t) = NULL;
+static PMEMblkpool *(*pmemblk_create) (const char *, size_t, size_t, mode_t);
+static PMEMblkpool *(*pmemblk_open) (const char *, size_t);
+static void (*pmemblk_close) (PMEMblkpool *);
+static size_t(*pmemblk_nblock) (PMEMblkpool *);
+static size_t(*pmemblk_bsize) (PMEMblkpool *);
+static int (*pmemblk_read) (PMEMblkpool *, void *, off_t);
+static int (*pmemblk_write) (PMEMblkpool *, const void *, off_t);