[fs.enum]

# 31 Input/output library [[input.output]](./#input.output)

## 31.12 File systems [[filesystems]](filesystems#fs.enum)

### 31.12.8 Enumerations [fs.enum]

#### [31.12.8.1](#path.format) Enum path​::​format [[fs.enum.path.format]](fs.enum.path.format)

[1](#path.format-1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L15695)

This enum specifies constants used to identify the format of the character
sequence, with the meanings listed in Table [148](#tab:fs.enum.path.format "Table 148: Enum path​::​format")[.](#path.format-1.sentence-1)

Table [148](#tab:fs.enum.path.format) — Enum path​::​format [[tab:fs.enum.path.format]](./tab:fs.enum.path.format)  

| [🔗](#tab:fs.enum.path.format-row-1)<br>**Name** | **Meaning** |
| --- | --- |
| [🔗](#tab:fs.enum.path.format-row-2)<br>native_format | The native pathname format[.](#tab:fs.enum.path.format-row-2-column-2-sentence-1) |
| [🔗](#tab:fs.enum.path.format-row-3)<br>generic_format | The generic pathname format[.](#tab:fs.enum.path.format-row-3-column-2-sentence-1) |
| [🔗](#tab:fs.enum.path.format-row-4)<br>auto_format | The interpretation of the format of the character sequence is  implementation-defined[.](#tab:fs.enum.path.format-row-4-column-2-sentence-1)<br>The implementation may inspect the content of the character sequence to  determine the format[.](#tab:fs.enum.path.format-row-4-column-2-sentence-2)<br>*Recommended practice*: For POSIX-based systems, native and generic formats are equivalent  and the character sequence should always be interpreted in the same way[.](#tab:fs.enum.path.format-row-4-column-2-sentence-3) |

#### [31.12.8.2](#file.type) Enum class file_type [[fs.enum.file.type]](fs.enum.file.type)

[1](#file.type-1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L15720)

This enum class specifies constants used to identify file types,
with the meanings listed in Table [149](#tab:fs.enum.file.type "Table 149: Enum class file_­type")[.](#file.type-1.sentence-1)

The values of the constants are distinct[.](#file.type-1.sentence-2)

Table [149](#tab:fs.enum.file.type) — Enum class file_type [[tab:fs.enum.file.type]](./tab:fs.enum.file.type)  

| [🔗](#tab:fs.enum.file.type-row-1)<br>**Constant** | **Meaning** |
| --- | --- |
| [🔗](#tab:fs.enum.file.type-row-2)<br>[none](#lib:file_type,none "31.12.8.2 Enum class file_­type [fs.enum.file.type]") | The type of the file has not been determined or an error occurred while  trying to determine the type[.](#tab:fs.enum.file.type-row-2-column-2-sentence-1) |
| [🔗](#tab:fs.enum.file.type-row-3)<br>[not_found](#lib:file_type,not_found "31.12.8.2 Enum class file_­type [fs.enum.file.type]") | Pseudo-type indicating the file was not found[.](#tab:fs.enum.file.type-row-3-column-2-sentence-1)<br>[*Note [1](#tab:fs.enum.file.type-row-3-column-2-note-1)*:<br>The file not being found is not considered an error while determining the type of a file[.](#tab:fs.enum.file.type-row-3-column-2-sentence-2) — *end note*] |
| [🔗](#tab:fs.enum.file.type-row-4)<br>[regular](#lib:file_type,regular "31.12.8.2 Enum class file_­type [fs.enum.file.type]") | Regular file |
| [🔗](#tab:fs.enum.file.type-row-5)<br>[directory](#lib:file_type,directory "31.12.8.2 Enum class file_­type [fs.enum.file.type]") | Directory file |
| [🔗](#tab:fs.enum.file.type-row-6)<br>[symlink](#lib:file_type,symlink "31.12.8.2 Enum class file_­type [fs.enum.file.type]") | Symbolic link file |
| [🔗](#tab:fs.enum.file.type-row-7)<br>[block](#lib:file_type,block "31.12.8.2 Enum class file_­type [fs.enum.file.type]") | Block special file |
| [🔗](#tab:fs.enum.file.type-row-8)<br>[character](#lib:file_type,character "31.12.8.2 Enum class file_­type [fs.enum.file.type]") | Character special file |
| [🔗](#tab:fs.enum.file.type-row-9)<br>[fifo](#lib:file_type,fifo "31.12.8.2 Enum class file_­type [fs.enum.file.type]") | FIFO or pipe file |
| [🔗](#tab:fs.enum.file.type-row-10)<br>[socket](#lib:file_type,socket "31.12.8.2 Enum class file_­type [fs.enum.file.type]") | Socket file |
| [🔗](#tab:fs.enum.file.type-row-11)<br>*implementation-defined* | Implementations that support file systems having file types in addition to the above file_type types shall supply implementation-defined file_type constants to separately identify each of those additional file types |
| [🔗](#tab:fs.enum.file.type-row-12)<br>[unknown](#lib:file_type,unknown "31.12.8.2 Enum class file_­type [fs.enum.file.type]") | The file exists but the type cannot be determined |

#### [31.12.8.3](#copy.opts) Enum class copy_options [[fs.enum.copy.opts]](fs.enum.copy.opts)

[1](#copy.opts-1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L15766)

The enum class type copy_options is a bitmask type ([[bitmask.types]](bitmask.types "16.3.3.3.3 Bitmask types")) that specifies bitmask constants used to control the semantics of
copy operations[.](#copy.opts-1.sentence-1)

The constants are specified in option groups with the meanings listed in Table [150](#tab:fs.enum.copy.opts "Table 150: Enum class copy_­options")[.](#copy.opts-1.sentence-2)

The constant none represents the empty bitmask, and
is shown in each option group for purposes of exposition;
implementations shall provide only a single definition[.](#copy.opts-1.sentence-3)

Every other constant in the table represents a distinct bitmask element[.](#copy.opts-1.sentence-4)

Table [150](#tab:fs.enum.copy.opts) — Enum class copy_options [[tab:fs.enum.copy.opts]](./tab:fs.enum.copy.opts)  

| [🔗](#tab:fs.enum.copy.opts-row-1)<br>**Option group controlling copy_file function effects for existing target files** | |
| --- | --- |
| [🔗](#tab:fs.enum.copy.opts-row-2)<br>**Constant** | **Meaning** |
| [🔗](#tab:fs.enum.copy.opts-row-3)<br>[none](#lib:copy_options,none "31.12.8.3 Enum class copy_­options [fs.enum.copy.opts]") | (Default) Error; file already exists[.](#tab:fs.enum.copy.opts-row-3-column-2-sentence-1) |
| [🔗](#tab:fs.enum.copy.opts-row-4)<br>[skip_existing](#lib:copy_options,skip_existing "31.12.8.3 Enum class copy_­options [fs.enum.copy.opts]") | Do not overwrite existing file, do not report an error[.](#tab:fs.enum.copy.opts-row-4-column-2-sentence-1) |
| [🔗](#tab:fs.enum.copy.opts-row-5)<br>[overwrite_existing](#lib:copy_options,overwrite_existing "31.12.8.3 Enum class copy_­options [fs.enum.copy.opts]") | Overwrite the existing file[.](#tab:fs.enum.copy.opts-row-5-column-2-sentence-1) |
| [🔗](#tab:fs.enum.copy.opts-row-6)<br>[update_existing](#lib:copy_options,update_existing "31.12.8.3 Enum class copy_­options [fs.enum.copy.opts]") | Overwrite the existing file if it is older than the replacement file[.](#tab:fs.enum.copy.opts-row-6-column-2-sentence-1) |
| [🔗](#tab:fs.enum.copy.opts-row-7)<br>**Option group controlling copy function effects for subdirectories** | |
| [🔗](#tab:fs.enum.copy.opts-row-8)<br>**Constant** | **Meaning** |
| [🔗](#tab:fs.enum.copy.opts-row-9)<br>[none](#lib:copy_options,none "31.12.8.3 Enum class copy_­options [fs.enum.copy.opts]") | (Default) Do not copy subdirectories[.](#tab:fs.enum.copy.opts-row-9-column-2-sentence-1) |
| [🔗](#tab:fs.enum.copy.opts-row-10)<br>[recursive](#lib:copy_options,recursive "31.12.8.3 Enum class copy_­options [fs.enum.copy.opts]") | Recursively copy subdirectories and their contents[.](#tab:fs.enum.copy.opts-row-10-column-2-sentence-1) |
| [🔗](#tab:fs.enum.copy.opts-row-11)<br>**Option group controlling copy function effects for symbolic links** | |
| [🔗](#tab:fs.enum.copy.opts-row-12)<br>**Constant** | **Meaning** |
| [🔗](#tab:fs.enum.copy.opts-row-13)<br>[none](#lib:copy_options,none "31.12.8.3 Enum class copy_­options [fs.enum.copy.opts]") | (Default) Follow symbolic links[.](#tab:fs.enum.copy.opts-row-13-column-2-sentence-1) |
| [🔗](#tab:fs.enum.copy.opts-row-14)<br>[copy_symlinks](#lib:copy_options,copy_symlinks "31.12.8.3 Enum class copy_­options [fs.enum.copy.opts]") | Copy symbolic links as symbolic links rather than copying the files that  they point to[.](#tab:fs.enum.copy.opts-row-14-column-2-sentence-1) |
| [🔗](#tab:fs.enum.copy.opts-row-15)<br>[skip_symlinks](#lib:copy_options,skip_symlinks "31.12.8.3 Enum class copy_­options [fs.enum.copy.opts]") | Ignore symbolic links[.](#tab:fs.enum.copy.opts-row-15-column-2-sentence-1) |
| [🔗](#tab:fs.enum.copy.opts-row-16)<br>**Option group controlling copy function effects for choosing the form of copying** | |
| [🔗](#tab:fs.enum.copy.opts-row-17)<br>**Constant** | **Meaning** |
| [🔗](#tab:fs.enum.copy.opts-row-18)<br>[none](#lib:copy_options,none "31.12.8.3 Enum class copy_­options [fs.enum.copy.opts]") | (Default) Copy content[.](#tab:fs.enum.copy.opts-row-18-column-2-sentence-1) |
| [🔗](#tab:fs.enum.copy.opts-row-19)<br>[directories_only](#lib:copy_options,directories_only "31.12.8.3 Enum class copy_­options [fs.enum.copy.opts]") | Copy directory structure only, do not copy non-directory files[.](#tab:fs.enum.copy.opts-row-19-column-2-sentence-1) |
| [🔗](#tab:fs.enum.copy.opts-row-20)<br>[create_symlinks](#lib:copy_options,create_symlinks "31.12.8.3 Enum class copy_­options [fs.enum.copy.opts]") | Make symbolic links instead of copies of files[.](#tab:fs.enum.copy.opts-row-20-column-2-sentence-1)<br>The source path shall be  an absolute path unless the destination path is in the current directory[.](#tab:fs.enum.copy.opts-row-20-column-2-sentence-2) |
| [🔗](#tab:fs.enum.copy.opts-row-21)<br>[create_hard_links](#lib:copy_options,create_hard_links "31.12.8.3 Enum class copy_­options [fs.enum.copy.opts]") | Make hard links instead of copies of files[.](#tab:fs.enum.copy.opts-row-21-column-2-sentence-1) |

#### [31.12.8.4](#perms) Enum class perms [[fs.enum.perms]](fs.enum.perms)

[1](#perms-1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L15823)

The enum class type perms is a bitmask type ([[bitmask.types]](bitmask.types "16.3.3.3.3 Bitmask types")) that specifies bitmask constants used to identify file
permissions, with the meanings listed in Table [151](#tab:fs.enum.perms "Table 151: Enum class perms")[.](#perms-1.sentence-1)

Table [151](#tab:fs.enum.perms) — Enum class perms [[tab:fs.enum.perms]](./tab:fs.enum.perms)  

| [🔗](#tab:fs.enum.perms-row-1)<br>**Name** | **Value** | **POSIX** | **Definition or notes** |
| --- | --- | --- | --- |
| [🔗](#tab:fs.enum.perms-row-2) | **(octal)** | **macro** |  |
| [🔗](#tab:fs.enum.perms-row-3)<br>[none](#lib:perms,none "31.12.8.4 Enum class perms [fs.enum.perms]") | 0 |  | There are no permissions set for the file[.](#tab:fs.enum.perms-row-3-column-4-sentence-1) |
| [🔗](#tab:fs.enum.perms-row-4)<br>[owner_read](#lib:perms,owner_read "31.12.8.4 Enum class perms [fs.enum.perms]") | 0400 | S_IRUSR | Read permission, owner |
| [🔗](#tab:fs.enum.perms-row-5)<br>[owner_write](#lib:perms,owner_write "31.12.8.4 Enum class perms [fs.enum.perms]") | 0200 | S_IWUSR | Write permission, owner |
| [🔗](#tab:fs.enum.perms-row-6)<br>[owner_exec](#lib:perms,owner_exec "31.12.8.4 Enum class perms [fs.enum.perms]") | 0100 | S_IXUSR | Execute/search permission, owner |
| [🔗](#tab:fs.enum.perms-row-7)<br>[owner_all](#lib:perms,owner_all "31.12.8.4 Enum class perms [fs.enum.perms]") | 0700 | S_IRWXU | Read, write, execute/search by owner;   owner_read | owner_write | owner_exec |
| [🔗](#tab:fs.enum.perms-row-8)<br>[group_read](#lib:perms,group_read "31.12.8.4 Enum class perms [fs.enum.perms]") | 040 | S_IRGRP | Read permission, group |
| [🔗](#tab:fs.enum.perms-row-9)<br>[group_write](#lib:perms,group_write "31.12.8.4 Enum class perms [fs.enum.perms]") | 020 | S_IWGRP | Write permission, group |
| [🔗](#tab:fs.enum.perms-row-10)<br>[group_exec](#lib:perms,group_exec "31.12.8.4 Enum class perms [fs.enum.perms]") | 010 | S_IXGRP | Execute/search permission, group |
| [🔗](#tab:fs.enum.perms-row-11)<br>[group_all](#lib:perms,group_all "31.12.8.4 Enum class perms [fs.enum.perms]") | 070 | S_IRWXG | Read, write, execute/search by group;   group_read | group_write | group_exec |
| [🔗](#tab:fs.enum.perms-row-12)<br>[others_read](#lib:perms,others_read "31.12.8.4 Enum class perms [fs.enum.perms]") | 04 | S_IROTH | Read permission, others |
| [🔗](#tab:fs.enum.perms-row-13)<br>[others_write](#lib:perms,others_write "31.12.8.4 Enum class perms [fs.enum.perms]") | 02 | S_IWOTH | Write permission, others |
| [🔗](#tab:fs.enum.perms-row-14)<br>[others_exec](#lib:perms,others_exec "31.12.8.4 Enum class perms [fs.enum.perms]") | 01 | S_IXOTH | Execute/search permission, others |
| [🔗](#tab:fs.enum.perms-row-15)<br>[others_all](#lib:perms,others_all "31.12.8.4 Enum class perms [fs.enum.perms]") | 07 | S_IRWXO | Read, write, execute/search by others;   others_read | others_write | others_exec |
| [🔗](#tab:fs.enum.perms-row-16)<br>[all](#lib:perms,all "31.12.8.4 Enum class perms [fs.enum.perms]") | 0777 |  | owner_all | group_all | others_all |
| [🔗](#tab:fs.enum.perms-row-17)<br>[set_uid](#lib:perms,set_uid "31.12.8.4 Enum class perms [fs.enum.perms]") | 04000 | S_ISUID | Set-user-ID on execution |
| [🔗](#tab:fs.enum.perms-row-18)<br>[set_gid](#lib:perms,set_gid "31.12.8.4 Enum class perms [fs.enum.perms]") | 02000 | S_ISGID | Set-group-ID on execution |
| [🔗](#tab:fs.enum.perms-row-19)<br>[sticky_bit](#lib:perms,sticky_bit "31.12.8.4 Enum class perms [fs.enum.perms]") | 01000 | S_ISVTX | Operating system dependent[.](#tab:fs.enum.perms-row-19-column-4-sentence-1) |
| [🔗](#tab:fs.enum.perms-row-20)<br>[mask](#lib:perms,mask "31.12.8.4 Enum class perms [fs.enum.perms]") | 07777 |  | all | set_uid | set_gid | sticky_bit |
| [🔗](#tab:fs.enum.perms-row-21)<br>[unknown](#lib:perms,unknown "31.12.8.4 Enum class perms [fs.enum.perms]") | 0xFFFF |  | The permissions are not known, such as when a file_status object  is created without specifying the permissions |

#### [31.12.8.5](#perm.opts) Enum class perm_options [[fs.enum.perm.opts]](fs.enum.perm.opts)

[1](#perm.opts-1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L15882)

The enum class type perm_options is a bitmask type ([[bitmask.types]](bitmask.types "16.3.3.3.3 Bitmask types")) that specifies bitmask constants used to
control the semantics of permissions operations,
with the meanings listed in Table [152](#tab:fs.enum.perm.opts "Table 152: Enum class perm_­options")[.](#perm.opts-1.sentence-1)

The bitmask constants are bitmask elements[.](#perm.opts-1.sentence-2)

In Table [152](#tab:fs.enum.perm.opts "Table 152: Enum class perm_­options") perm denotes a value of type perms passed to permissions[.](#perm.opts-1.sentence-3)

Table [152](#tab:fs.enum.perm.opts) — Enum class perm_options [[tab:fs.enum.perm.opts]](./tab:fs.enum.perm.opts)  

| [🔗](#tab:fs.enum.perm.opts-row-1)<br>**Name** | **Meaning** |
| --- | --- |
| [🔗](#tab:fs.enum.perm.opts-row-2)<br>[replace](#lib:perm_options,replace "31.12.8.5 Enum class perm_­options [fs.enum.perm.opts]") | permissions shall replace the file's permission bits with perm |
| [🔗](#tab:fs.enum.perm.opts-row-3)<br>[add](#lib:perm_options,add "31.12.8.5 Enum class perm_­options [fs.enum.perm.opts]") | permissions shall replace the file's permission bits with  the bitwise or of perm and the file's current permission bits[.](#tab:fs.enum.perm.opts-row-3-column-2-sentence-1) |
| [🔗](#tab:fs.enum.perm.opts-row-4)<br>[remove](#lib:perm_options,remove "31.12.8.5 Enum class perm_­options [fs.enum.perm.opts]") | permissions shall replace the file's permission bits with  the bitwise and of the complement of perm and the file's current permission bits[.](#tab:fs.enum.perm.opts-row-4-column-2-sentence-1) |
| [🔗](#tab:fs.enum.perm.opts-row-5)<br>[nofollow](#lib:perm_options,nofollow "31.12.8.5 Enum class perm_­options [fs.enum.perm.opts]") | permissions shall change the permissions of a symbolic link itself  rather than the permissions of the file the link resolves to[.](#tab:fs.enum.perm.opts-row-5-column-2-sentence-1) |

#### [31.12.8.6](#dir.opts) Enum class directory_options [[fs.enum.dir.opts]](fs.enum.dir.opts)

[1](#dir.opts-1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L15913)

The enum class type directory_options is a bitmask
 type ([[bitmask.types]](bitmask.types "16.3.3.3.3 Bitmask types")) that specifies bitmask constants used to identify
 directory traversal options, with the meanings listed in Table [153](#tab:fs.enum.dir.opts "Table 153: Enum class directory_­options")[.](#dir.opts-1.sentence-1)

The constant none represents the empty bitmask;
 every other constant in the table represents a distinct bitmask element[.](#dir.opts-1.sentence-2)

Table [153](#tab:fs.enum.dir.opts) — Enum class directory_options [[tab:fs.enum.dir.opts]](./tab:fs.enum.dir.opts)  

| [🔗](#tab:fs.enum.dir.opts-row-1)<br>**Name** | **Meaning** |
| --- | --- |
| [🔗](#tab:fs.enum.dir.opts-row-2)<br>[none](#lib:directory_options,none "31.12.8.6 Enum class directory_­options [fs.enum.dir.opts]") | (Default) Skip directory symlinks, permission denied is an error[.](#tab:fs.enum.dir.opts-row-2-column-2-sentence-1) |
| [🔗](#tab:fs.enum.dir.opts-row-3)<br>[follow_directory_symlink](#lib:directory_options,follow_directory_symlink "31.12.8.6 Enum class directory_­options [fs.enum.dir.opts]") | Follow rather than skip directory symlinks[.](#tab:fs.enum.dir.opts-row-3-column-2-sentence-1) |
| [🔗](#tab:fs.enum.dir.opts-row-4)<br>[skip_permission_denied](#lib:directory_options,skip_permission_denied "31.12.8.6 Enum class directory_­options [fs.enum.dir.opts]") | Skip directories that would otherwise result in permission denied[.](#tab:fs.enum.dir.opts-row-4-column-2-sentence-1) |