29 Input/output library [input.output]

29.11 File systems [filesystems]

29.11.14 Filesystem operation functions [fs.op.funcs] Absolute [fs.op.absolute]

path absolute(const path& p); path absolute(const path& p, error_code& ec);
Effects: Composes an absolute path referencing the same file system location as p according to the operating system ([fs.conform.os]).
Returns: The composed path.
The signature with argument ec returns path() if an error occurs.
For the returned path, rp, rp.is_­absolute() is true unless an error occurs.
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Throws: As specified in [fs.err.report].
To resolve symlinks, or perform other sanitization which might require queries to secondary storage, such as hard disks, consider canonical ([fs.op.canonical]).
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Implementations are strongly encouraged to not query secondary storage, and not consider !exists(p) an error.
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For POSIX-based operating systems, absolute(p) is simply current_­path()/p.
For Windows-based operating systems, absolute might have the same semantics as GetFullPathNameW.
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