diff --git a/src/spiffs.h b/src/spiffs.h
index cdb418b..0758646 100644
--- a/src/spiffs.h
+++ b/src/spiffs.h
@@ -147,20 +147,28 @@ typedef void (*spiffs_file_callback)(struct spiffs_t *fs, spiffs_fileop_type op,
 
 /* Any write to the filehandle is appended to end of the file */
 #define SPIFFS_APPEND                   (1<<0)
+#define SPIFFS_O_APPEND                 SPIFFS_APPEND
 /* If the opened file exists, it will be truncated to zero length before opened */
 #define SPIFFS_TRUNC                    (1<<1)
+#define SPIFFS_O_TRUNC                  SPIFFS_TRUNC
 /* If the opened file does not exist, it will be created before opened */
 #define SPIFFS_CREAT                    (1<<2)
+#define SPIFFS_O_CREAT                  SPIFFS_CREAT
 /* The opened file may only be read */
 #define SPIFFS_RDONLY                   (1<<3)
-/* The opened file may only be writted */
+#define SPIFFS_O_RDONLY                 SPIFFS_RDONLY
+/* The opened file may only be written */
 #define SPIFFS_WRONLY                   (1<<4)
-/* The opened file may be both read and writted */
+#define SPIFFS_O_WRONLY                 SPIFFS_WRONLY
+/* The opened file may be both read and written */
 #define SPIFFS_RDWR                     (SPIFFS_RDONLY | SPIFFS_WRONLY)
-/* Any writes to the filehandle will never be cached */
+#define SPIFFS_O_RDWR                   SPIFFS_RDWR
+/* Any writes to the filehandle will never be cached but flushed directly */
 #define SPIFFS_DIRECT                   (1<<5)
-/* If SPIFFS_CREAT and SPIFFS_EXCL are set, SPIFFS_open() shall fail if the file exists */
+#define SPIFFS_O_DIRECT                 SPIFFS_DIRECT
+/* If SPIFFS_O_CREAT and SPIFFS_O_EXCL are set, SPIFFS_open() shall fail if the file exists */
 #define SPIFFS_EXCL                     (1<<6)
+#define SPIFFS_O_EXCL                   SPIFFS_EXCL
 
 #define SPIFFS_SEEK_SET                 (0)
 #define SPIFFS_SEEK_CUR                 (1)
@@ -377,8 +385,8 @@ s32_t SPIFFS_creat(spiffs *fs, const char *path, spiffs_mode mode);
  * @param fs            the file system struct
  * @param path          the path of the new file
  * @param flags         the flags for the open command, can be combinations of
- *                      SPIFFS_APPEND, SPIFFS_TRUNC, SPIFFS_CREAT, SPIFFS_RD_ONLY,
- *                      SPIFFS_WR_ONLY, SPIFFS_RDWR, SPIFFS_DIRECT
+ *                      SPIFFS_O_APPEND, SPIFFS_O_TRUNC, SPIFFS_O_CREAT, SPIFFS_O_RDONLY,
+ *                      SPIFFS_O_WRONLY, SPIFFS_O_RDWR, SPIFFS_O_DIRECT, SPIFFS_O_EXCL
  * @param mode          ignored, for posix compliance
  */
 spiffs_file SPIFFS_open(spiffs *fs, const char *path, spiffs_flags flags, spiffs_mode mode);
diff --git a/src/spiffs_hydrogen.c b/src/spiffs_hydrogen.c
index 69a47e6..bb92a5e 100644
--- a/src/spiffs_hydrogen.c
+++ b/src/spiffs_hydrogen.c
@@ -225,7 +225,7 @@ spiffs_file SPIFFS_open(spiffs *fs, const char *path, spiffs_flags flags, spiffs
   SPIFFS_API_CHECK_RES_UNLOCK(fs, res);
 
   res = spiffs_object_find_object_index_header_by_name(fs, (const u8_t*)path, &pix);
-  if ((flags & SPIFFS_CREAT) == 0) {
+  if ((flags & SPIFFS_O_CREAT) == 0) {
     if (res < SPIFFS_OK) {
       spiffs_fd_return(fs, fd->file_nbr);
     }
@@ -233,14 +233,14 @@ spiffs_file SPIFFS_open(spiffs *fs, const char *path, spiffs_flags flags, spiffs
   }
 
   if (res == SPIFFS_OK &&
-      (flags & (SPIFFS_CREAT | SPIFFS_EXCL)) == (SPIFFS_CREAT | SPIFFS_EXCL)) {
+      (flags & (SPIFFS_O_CREAT | SPIFFS_O_EXCL)) == (SPIFFS_O_CREAT | SPIFFS_O_EXCL)) {
     // creat and excl and file exists - fail
     res = SPIFFS_ERR_FILE_EXISTS;
     spiffs_fd_return(fs, fd->file_nbr);
     SPIFFS_API_CHECK_RES_UNLOCK(fs, res);
   }
 
-  if ((flags & SPIFFS_CREAT) && res == SPIFFS_ERR_NOT_FOUND) {
+  if ((flags & SPIFFS_O_CREAT) && res == SPIFFS_ERR_NOT_FOUND) {
 #if !SPIFFS_READ_ONLY
     spiffs_obj_id obj_id;
     // no need to enter conflicting name here, already looked for it above
@@ -254,7 +254,7 @@ spiffs_file SPIFFS_open(spiffs *fs, const char *path, spiffs_flags flags, spiffs
       spiffs_fd_return(fs, fd->file_nbr);
     }
     SPIFFS_API_CHECK_RES_UNLOCK(fs, res);
-    flags &= ~SPIFFS_TRUNC;
+    flags &= ~SPIFFS_O_TRUNC;
 #endif // !SPIFFS_READ_ONLY
   } else {
     if (res < SPIFFS_OK) {
@@ -268,7 +268,7 @@ spiffs_file SPIFFS_open(spiffs *fs, const char *path, spiffs_flags flags, spiffs
   }
   SPIFFS_API_CHECK_RES_UNLOCK(fs, res);
 #if !SPIFFS_READ_ONLY
-  if (flags & SPIFFS_TRUNC) {
+  if (flags & SPIFFS_O_TRUNC) {
     res = spiffs_object_truncate(fd, 0, 0);
     if (res < SPIFFS_OK) {
       spiffs_fd_return(fs, fd->file_nbr);
@@ -300,7 +300,7 @@ spiffs_file SPIFFS_open_by_dirent(spiffs *fs, struct spiffs_dirent *e, spiffs_fl
   }
   SPIFFS_API_CHECK_RES_UNLOCK(fs, res);
 #if !SPIFFS_READ_ONLY
-  if (flags & SPIFFS_TRUNC) {
+  if (flags & SPIFFS_O_TRUNC) {
     res = spiffs_object_truncate(fd, 0, 0);
     if (res < SPIFFS_OK) {
       spiffs_fd_return(fs, fd->file_nbr);
@@ -346,7 +346,7 @@ spiffs_file SPIFFS_open_by_page(spiffs *fs, spiffs_page_ix page_ix, spiffs_flags
   SPIFFS_API_CHECK_RES_UNLOCK(fs, res);
 
 #if !SPIFFS_READ_ONLY
-  if (flags & SPIFFS_TRUNC) {
+  if (flags & SPIFFS_O_TRUNC) {
     res = spiffs_object_truncate(fd, 0, 0);
     if (res < SPIFFS_OK) {
       spiffs_fd_return(fs, fd->file_nbr);
@@ -374,7 +374,7 @@ s32_t SPIFFS_read(spiffs *fs, spiffs_file fh, void *buf, s32_t len) {
   res = spiffs_fd_get(fs, fh, &fd);
   SPIFFS_API_CHECK_RES_UNLOCK(fs, res);
 
-  if ((fd->flags & SPIFFS_RDONLY) == 0) {
+  if ((fd->flags & SPIFFS_O_RDONLY) == 0) {
     res = SPIFFS_ERR_NOT_READABLE;
     SPIFFS_API_CHECK_RES_UNLOCK(fs, res);
   }
@@ -457,12 +457,12 @@ s32_t SPIFFS_write(spiffs *fs, spiffs_file fh, void *buf, s32_t len) {
   res = spiffs_fd_get(fs, fh, &fd);
   SPIFFS_API_CHECK_RES_UNLOCK(fs, res);
 
-  if ((fd->flags & SPIFFS_WRONLY) == 0) {
+  if ((fd->flags & SPIFFS_O_WRONLY) == 0) {
     res = SPIFFS_ERR_NOT_WRITABLE;
     SPIFFS_API_CHECK_RES_UNLOCK(fs, res);
   }
 
-  if ((fd->flags & SPIFFS_APPEND)) {
+  if ((fd->flags & SPIFFS_O_APPEND)) {
     fd->fdoffset = fd->size == SPIFFS_UNDEFINED_LEN ? 0 : fd->size;
   }
 
@@ -474,7 +474,7 @@ s32_t SPIFFS_write(spiffs *fs, spiffs_file fh, void *buf, s32_t len) {
     fd->cache_page = spiffs_cache_page_get_by_fd(fs, fd);
   }
 #endif
-  if (fd->flags & SPIFFS_APPEND) {
+  if (fd->flags & SPIFFS_O_APPEND) {
     if (fd->size == SPIFFS_UNDEFINED_LEN) {
       offset = 0;
     } else {
@@ -488,7 +488,7 @@ s32_t SPIFFS_write(spiffs *fs, spiffs_file fh, void *buf, s32_t len) {
   }
 
 #if SPIFFS_CACHE_WR
-  if ((fd->flags & SPIFFS_DIRECT) == 0) {
+  if ((fd->flags & SPIFFS_O_DIRECT) == 0) {
     if (len < (s32_t)SPIFFS_CFG_LOG_PAGE_SZ(fs)) {
       // small write, try to cache it
       u8_t alloc_cpage = 1;
@@ -672,7 +672,7 @@ s32_t SPIFFS_fremove(spiffs *fs, spiffs_file fh) {
   res = spiffs_fd_get(fs, fh, &fd);
   SPIFFS_API_CHECK_RES_UNLOCK(fs, res);
 
-  if ((fd->flags & SPIFFS_WRONLY) == 0) {
+  if ((fd->flags & SPIFFS_O_WRONLY) == 0) {
     res = SPIFFS_ERR_NOT_WRITABLE;
     SPIFFS_API_CHECK_RES_UNLOCK(fs, res);
   }
@@ -771,7 +771,7 @@ static s32_t spiffs_fflush_cache(spiffs *fs, spiffs_file fh) {
   res = spiffs_fd_get(fs, fh, &fd);
   SPIFFS_API_CHECK_RES(fs, res);
 
-  if ((fd->flags & SPIFFS_DIRECT) == 0) {
+  if ((fd->flags & SPIFFS_O_DIRECT) == 0) {
     if (fd->cache_page == 0) {
       // see if object id is associated with cache already
       fd->cache_page = spiffs_cache_page_get_by_fd(fs, fd);