| access, accessx, or faccessx  | 
  Determines accessibility of a file. | 
| fclear | 
  Clears space in a file. | 
| fcntl, dup, or dup2  | 
  Controls open file descriptors. | 
| fsync  | 
  Writes changes in a file to permanent storage. | 
| getenv  | 
  Returns the value of an environment variable. | 
| getutent, getutid, getutline, putuline, setutent, endutent, or utmpname | 
|   | 
 Accesses utmp file entries. | 
| getutid_r, getutline_r, pututline_r, setutent_r, endutent_r, or utmpname_r | 
|   | 
  Accesses  utmp file entries. | 
|   Moves the read-write pointer in an open file. | 
| lockfx, lockf, or flock | 
  Controls open file descriptor locks. | 
| mknod or mkfifo | 
  Creates regular, FIFO, or special files. | 
| mktemp or mkstemp  | 
  Constructs a unique file name. | 
| open, openx, or creat | 
  Returns a file descriptor and creates files. | 
| pclose  | 
  Closes an open pipe. | 
| pipe  | 
  Creates an interprocess channel. | 
| popen | 
  Initiates a pipe to a process. | 
| pathconf, fpathconf | 
  Retrieves file implementation characteristics. | 
| putenv | 
  Sets an environment variable. | 
| read, readx, readv, readvx  | 
  Read from a file or device.  | 
| rename | 
  Renames directory or file within a file system. | 
| statx, stat, fstatx, fstat, fullstat, fullstat  | 
|   | 
  Gets file status. | 
| tmpfile  | 
  Creates a temporary file. | 
| tmpnam or tempnam | 
  Constructs a name for a temporary file. | 
| truncate, ftruncate | 
  Makes a file shorter. | 
| umask | 
  Gets and sets the value of the file creation mask. | 
| utimes or utime | 
  Sets file access or modification time. | 
| write, writex, writev, writevx  | 
  Writes to a file or device. | 
| Error Codes for Services that Require Path-Name Resolution | 
| chdir  | 
  Changes the current working directory. | 
| chroot  | 
  Changes the effective root directory. | 
| getwd, getcwd | 
  Gets the current directory path name. | 
| glob  | 
  Generates a list of path names to accessible files. | 
| globfree | 
  Frees all memory associated with the pglob parameter. | 
| link  | 
  Creates additional directory entry for an existing file. | 
| mkdir | 
  Creates a directory. | 
| opendir, readdir, telldir, seekdir, rewinddir, closedir | 
|   | 
  Performs operations on directories. | 
| readdir_r | 
  Reads a directory. | 
| rmdir | 
  Removes a directory. | 
| scandir, alphasort | 
  Scans a directory. | 
| readlink | 
  Reads the volume of a symbolic link. | 
| remove | 
  Makes a file inaccessible by specified name. | 
| symlink | 
  Creates a symbolic link to a file. | 
| unlink | 
  Removes a directory entry. | 
| confstr | 
  Determines the current value of a specified system variable defined by a string. | 
| fscntl | 
  Manipulates file system control operations. | 
| getfsent, getfsspec, getfsfile, getfstype, setfsent, or endfsent  | 
|   | 
  Gets information about a file system. | 
| getfsent_r, getfsspec_r, getfsfile_r, getfstype_r, setfsent_r, or endfsent_r | 
|   | 
  Gets information about a file system. | 
| getvfsent, getvfsbytype, getvfsbyname, getvfsbyflag, setvfsent, endvfsent  | 
|   | 
  Gets information about virtual file system entries. | 
| mnctl | 
  Returns mount status information. | 
| quotactl | 
  Manipulates disk quotas. | 
| statfs, fstatfs | 
  Gets the status of a file's file system. | 
| sysconf | 
  Reports current value of system limits or options. | 
| sync | 
  Updates all file systems information to disk. | 
| umask | 
  Gets and sets the value of the file creation mask. | 
| vmount | 
  Mounts a file system | 
| umount, uvmount | 
  Removes a virtual file system from the file tree. |