Standard libraries

<assert.h> Conditionally compiled macro that compares its argument to zero
<dirent.h> Contains constructs that facilitate directory traversing
<errno.h> Macros reporting error conditions
<mntent.h> Contains functions that helps read mount entries
<stdio.h> Input/Output
<stdlib.h> General utilities
<string.h> String handling
<unistd.h> Various essential POSIX functions and constants
<time.h> Time management functions
<sys/ioctl.h> Input/Output manipulation functions
<sys/mount.h> File system mount functions
<sys/stat.h> File statistics and permissions
<sys/statfs.h> File system statistics
<sys/types.h> Operating system types