platform/libc

A malloc result: a block, or no_allocation.

A readdir result: the next record, or no_directory.

C's struct dirent as readdir returns it. glibc gives no name length: the name ends at its NUL.

C's struct dirent as readdir returns it, with the 64-bit inode every arm64 Darwin has.

C's struct dirent as readdir returns it, in the layout FreeBSD 12 gave it with 64-bit inodes.

An fdopendir result: a directory stream, DIR *, or no_directory.

C's struct stat, as stat fills it on this system.

C's struct stat, as stat fills it on this system.

C's struct stat, as stat fills it on this system.

C's struct stat, as stat fills it on this system. C declares dev_t as int32_t here, but a device number is a bit pattern, not a quantity, and devfs's may have the sign bit set, so both device fields are unsigned and widening them never traps.

poll's count of records, C's nfds_t.

poll's count of records, C's nfds_t.

One record poll reads and fills, C's struct pollfd: the descriptor to watch, the events asked about and the events that happened. A negative descriptor is ignored. The same on every hosted system.

C's struct timespec: whole seconds and the nanoseconds after them.

What malloc returns when it cannot allocate: C's null pointer.

What fdopendir gives when it cannot open a directory stream, and readdir at the end or on a failure: C's null pointer.

The directory descriptor that makes an *at call's relative path relative to the working directory.

The directory descriptor that makes an *at call's relative path relative to the working directory.

The directory descriptor that makes an *at call's relative path relative to the working directory.

unlinkat flag: remove an empty directory rather than a file.

unlinkat flag: remove an empty directory rather than a file.

unlinkat flag: remove an empty directory rather than a file.

fstatat flag: report a symbolic link itself.

fstatat flag: report a symbolic link itself.

fstatat flag: report a symbolic link itself.

d_type: a directory.

d_type: a symbolic link.

d_type: a regular file.

A struct dirent's d_type: the entry's type is not known, and a status call relative to the directory tells it. The values are the same on every hosted system.

errno: permission denied.

errno: the name already exists. The same on every hosted system.

errno: interrupted by a signal before anything was transferred.

errno: no such file or directory.

errno: a path component is not a directory.

errno: the operation is not permitted. The same on every hosted system.

errno: the file system is read-only.

sizeof (struct stat) in the native C headers.

sizeof (struct stat) in the native C headers.

sizeof (struct stat) in the native C headers.

sizeof (struct stat) in the native C headers.

mmap flag: the mapping is backed by no file and starts zeroed.

mmap flag: the mapping is backed by no file and starts zeroed.

What mmap returns when it fails: C's MAP_FAILED, all bits set.

mmap flag: the mapping is private to this process.

open flag: every write goes to the end of the file.

open flag: every write goes to the end of the file.

open flag: create the file if it does not exist. Linux keeps one value on every architecture; Darwin and FreeBSD share the BSD one.

open flag: create the file if it does not exist. Linux keeps one value on every architecture; Darwin and FreeBSD share the BSD one.

open flag: fail with ENOTDIR unless the path names a directory. Linux's arm64 keeps a value of its own.

open flag: fail with ENOTDIR unless the path names a directory. Linux's arm64 keeps a value of its own.

open flag: fail with ENOTDIR unless the path names a directory. Linux's arm64 keeps a value of its own.

open flag: fail with ENOTDIR unless the path names a directory. Linux's arm64 keeps a value of its own.

open flag: with o_creat, fail with EEXIST if the name is taken.

open flag: with o_creat, fail with EEXIST if the name is taken.

open flag: read only. The same on every hosted system.

open flag: read and write. The same on every hosted system.

open flag: truncate an existing regular file to length zero.

open flag: truncate an existing regular file to length zero.

open flag: write only. The same on every hosted system.

mmap protection: the pages may be read. The same on every hosted system.

mmap protection: the pages may be written.

stat mode: a directory.

stat mode: a symbolic link.

A stat mode's file-type bits, and the types among them. The same on every hosted system.

stat mode: a regular file.

End the process with status at once: no atexit handler runs and no C stream is flushed.

Close descriptor: 0, or -1 with the reason in errno. The descriptor may be released even when this fails, so a failed close is never retried.

Close a directory stream and its descriptor: 0, or -1 with the reason in errno. The stream is released either way.

The calling thread's errno cell, __errno_location on Linux and __error on Darwin and FreeBSD. Read it immediately after the failing call, before any other call that may set it.

The calling thread's errno cell, __errno_location on Linux and __error on Darwin and FreeBSD. Read it immediately after the failing call, before any other call that may set it.

A directory stream over the directory open as descriptor, which the stream then owns and closedir closes, or no_directory with the reason in errno.

Give a block from malloc back to the C library.

Fill result with the status of path, relative to the directory open as directory: 0, or -1 with the reason in errno. With at_symlink_nofollow in flags a symbolic link is reported itself.

The size of a page in bytes, 16 KiB on Darwin arm64 and 4 KiB on the others.

Allocate size bytes aligned for any C object, or no_allocation. malloc(0) may return either; a caller that needs a distinct block for an empty request asks for a nonzero size.

Make the directory path, relative to directory (or at_fdcwd), with the permission bits mode, which the process umask filters: 0, or -1 with the reason in errno.

Make the directory path, relative to directory (or at_fdcwd), with the permission bits mode, which the process umask filters: 0, or -1 with the reason in errno.

Make the directory path, relative to directory (or at_fdcwd), with the permission bits mode, which the process umask filters: 0, or -1 with the reason in errno.

Map length bytes, at a place of the system's choosing when address is zero: the mapping's address, or map_failed with the reason in errno. With map_anonymous the descriptor is -1 and the offset zero.

Unmap the length bytes at address: 0, or -1 with the reason in errno.

Open the file at the NUL-terminated path and return its descriptor, or -1 with the reason in errno. flags is o_rdonly or o_wronly, or'd with o_creat and o_trunc; with o_creat the one variadic argument is the new file's permission bits as an i32, which the process umask filters.

Open path, relative to the directory open as directory (or at_fdcwd), as open does: the new descriptor, or -1 with the reason in errno. With o_creat the one variadic argument is the permission bits as an i32.

Wait until one of the count records at records has an event, or timeout milliseconds pass, waiting indefinitely when it is negative: the number of records with an event, zero when the time passed first, or -1 with the reason in errno.

Read at most length bytes from descriptor into data. The count read, zero at end of file, or -1 with the reason in errno. EINTR means nothing was transferred.

The stream's next record, good until the next readdir or closedir on it, or no_directory at the end and on a failure, which errno tells apart when the caller zeroed it first. Records include . and ...

Fill result with the status of the file path names, following symbolic links: 0, or -1 with the reason in errno.

The number of bytes before the first NUL at text.

Remove the name path, relative to directory (or at_fdcwd): a file with flags zero, an empty directory with at_removedir. 0, or -1 with the reason in errno.

Write at most length bytes from data to descriptor. The count accepted, which may be short, or -1 with the reason in errno. EINTR means nothing was transferred.