What is the difference between remove and unlink functions in C++?
- I doubt you will notice any difference in speed. Making the choice will not be the costly part of the operation.Loki Astari– Loki Astari2013-02-28 00:05:08 +00:00Commented Feb 28, 2013 at 0:05
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5 Answers
Apart from the fact that unlink is unix-specific (as pointed out by Chris), we read in the POSIX manual:
If path does not name a directory, remove(path) is equivalent to unlink(path). If path names a directory, remove(path) is equivalent to rmdir(path).
As for the directory-passed unlink, we read:
The path argument must not name a directory unless the process has appropriate privileges and the implementation supports using unlink() on directories. (...) Applications should use rmdir() to remove a directory.
answered Feb 3, 2010 at 14:09
Kornel Kisielewicz
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remove is portable, and unlink is Unix-specific. :-P
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The remove() function removes the file or directory specified by path.
If path specifies a directory, remove(path) is the equivalent of rmdir(path). Otherwise, it is the equivalent of unlink(path).
From: man remove.
Good Luck ;)
1 Comment
Keith Thompson
Note that that's specific to Unix-like systems (which is perfectly appropriate given the tags on the question). The ISO C standard defines the
remove function; it says nothing about directories. POSIX extends its behavior as you describe.unlink is not unix-specific, i don't know why people're saying that. see io.h. although you'll probably have to do something like
#define unlink _unlink http://msdn.microsoft.com/en-us/library/1c3tczd6%28v=VS.100%29.aspx
http://msdn.microsoft.com/en-us/library/2da4hk1d%28v=VS.100%29.aspx
3 Comments
Adrian McCarthy
unlink is a Posix function. MS included many Posix functions in the C runtime headers for their compiler, but this polluted the namespace. To be more compliant with the C standard, MS later replaced some of the Posix functions they had provided with versions prefixed with an underscore (and removed others). Leading underscores are reserved to the implementation. In general, C runtime functions are more portable than Posix functions. Posix functions, in general, are pretty unix-centric, even though some non-unix OSes may provide some Posix support.
Adrian McCarthy
No, we do not agree. unlink is a Posix function. Posix was an attempt to standardize Unix-derived operating systems. _unlink is a different function that works on a non-Unix operating system.
Michele
It may be a unix function, but you can define it so that if it finds unlink in the code when it's the windows OS, it actually goes to the definition of _unlink. I think that's what @bviktor was alluding to.
remove() is part of the C++ standard (N4860 29.11.14.30). unlink() is not.
