littlefs

https://github.com/ARMmbed/littlefs

Uses for loops with initialisation, so C99 is required. -std=c99 will need to be added to compiler options.

lfs_util.h contains a few debug/error macros, which utilise printf, so depending on whether your system has printf you may get warnings to deal with.

Suggested option in lfs_utils.h is to write your own config file and use -DLFS_CONFIG=lfs_config.h to have it included instead of lfs_utils.h, which means you need to copy and adjust anything needed.

If your system does not have printf, you can take the easy option at least initially and disable them using compiler defines (see lfs_util.h). LFS_NO_DEBUG, LFS_NO_WARN, LFS_NO_ERROR, LFS_NO_ASSERT Alternatively you need to provide a printf, or replace printf with an appropriate debug print function on your system.

Additionally if you have a very restricted microcontroller, its likely you will want to set both or one of define LFS_NO_MALLOC, LFS_NO_ASSERT The first ensuring that memory allocation is not used, and the second if you do not want assert functionality.