Interpretations

Answering questions that may arise related to the meaning of portions of an IEEE standard concerning specific applications.

IEEE Standards Interpretations for IEEE Std 1003.1™-2001 IEEE Standard for Information Technology - Portable Operating System Interface (POSIX®)

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Interpretation Request #5
Topic:
Defect in XSH unlink Relevant Sections: unlink

The unlink() function defines the following error condition [EPERM] The file named by path is a directory, and either the calling process does not have appropriate privileges, or the implementation prohibits using unlink() on directories. The EISDIR error condition would also seem an appropriate error to return in the case when unlink() is attempted on a directory. Is an implementation conforming that returns EISDIR rather than EPERM ? A certain body of implementors believe that this is the more natural error code to expect in this case.

Proposed Interpretation
The standard is clear on the requirements, however concerns should be forwarded to the sponsor to consider allowing the EISDIR error.

Proposed Rationale
Applications receiving an error should be able to cope with any unexpected error code. The EISDIR code would seem a logical return.

Interpretation Response
The standard clearly states that unlink() on a directory returns EPERM for this condition,and conforming implementations must conform to this.

Rationale for Interpretation
The standard is clear. Only EPERM is defined for this error. To make a change would reduce the consensus.