Interpretations

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

IEEE Standards Interpretation for IEEE Std 1003.1™-1990 IEEE Standard for Information Technology--Portable Operating System Interfaces (POSIX®)

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Interpretation Request #72
Topic: write and EFBIG Relevant Sections: 6.4.2.4

In Section 6.4.2.4 [errno values returned from write()], there is an entry for EFBIG (lines 275- 276, page 121): An attempt was made to write a file that exceeds an implementation-defined maximum file size. The question regards the phrase "maximum file size". Does this phrase refer to the "maximum size that a file can possibly or theoretically become on the given implementation" or can it also mean such things as "maximum file size allowed to this process by the implementation"? On many operating systems, a per-process file size limit can be set. Is it conforming for the implementation to set EFBIG when a process' write() hits this limit? It appears to me that this would be conforming behavior, since this also is an "implementation- defined maximum file size", for that process.

Interpretation Response
The standard clearly states the requirements for write() and the EFBIG error and permits this behavior so long as this limit is described in the accompanying conformance documentation.

Rationale for Interpretation
None.