View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0000187 | 1003.1(2008)/Issue 7 | Shell and Utilities | public | 2009-11-23 04:48 | 2013-04-16 13:06 |
| Reporter | Vincent Lefevre | Assigned To | ajosey | ||
| Priority | normal | Severity | Objection | Type | Enhancement Request |
| Status | Closed | Resolution | Accepted As Marked | ||
| Name | Vincent Lefèvre | ||||
| Organization | INRIA | ||||
| User Reference | |||||
| Section | c99 | ||||
| Page Number | 2489 | ||||
| Line Number | 79574-79582 | ||||
| Interp Status | Approved | ||||
| Final Accepted Text | 0000187:0000322 | ||||
| Summary | 0000187: Specification of c99 -I option should introduce the concept of system directories | ||||
| Description | POSIX says: "For headers whose names are enclosed in angle brackets ("<>"), the header shall be searched for only in directories named in -I options and then in the usual places." However some implementations such as GCC (e.g. used via c99 under Linux) do not behave in that way, and developers regard that as a defect in POSIX. See e.g. http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40442 which has been closed with the comment "Not a GCC bug, the POSIX list generally agreed the effects of reordering system directories should be unspecified or undefined." | ||||
| Desired Action | POSIX should introduce the concept of system directories and say what happens when reordering such directories (e.g. unspecified behavior). However this isn't clear to me, because headers from user/admin-installed libraries are often found in such directories (typically /usr/local/include), and there should also be some standard way to put such directories behind some other ones (e.g. /opt/local/include). | ||||
| Tags | tc1-2008 | ||||
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When this issue was discussed on the mailing list, mention was made of C99 section 7.1.2 para 3, which says: If a file with the same name as one of the above < and > delimited sequences, not provided as part of the implementation, is placed in any of the standard places that are searched for included source files, the behavior is undefined. (This is preceded by a list of all the standard headers in C99, within < ... >) As part of the changes made to address this bug, we should include something which extends C99 section 7.1.2 para 3 to cover the standard POSIX headers that are not in C99. |
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Interpretation response ------------------------ The standard states the requirements for c99 -I, and conforming implementations must conform to this. However, concerns have been raised about this which are being referred to the sponsor. Rationale: ------------- None. Notes to the Editor (not part of this interpretation): ------------------------------------------------------- At page 2489 line 79580 after: Directories named in -I options shall be searched in the order specified. add: If the -I option is used to specify a directory that is one of the usual places searched by default, the results are unspecified. At page 2489 line 79585 after: Directories named in -L options shall be searched in the order specified. add: If the -L option is used to specify a directory that is one of the usual places searched by default, the results are unspecified. After page 2492 line 79718 add a new unnumbered heading and a new paragraph: Header Search If a file with the same name as one of the standard headers defined in [xref to XBD section 13], not provided as part of the implementation, is placed in any of the usual places that are searched by default for headers, the results are unspecified. |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2009-11-23 04:48 | Vincent Lefevre | New Issue | |
| 2009-11-23 04:48 | Vincent Lefevre | Status | New => Under Review |
| 2009-11-23 04:48 | Vincent Lefevre | Assigned To | => ajosey |
| 2009-11-23 04:48 | Vincent Lefevre | Name | => Vincent Lefèvre |
| 2009-11-23 04:48 | Vincent Lefevre | Organization | => INRIA |
| 2009-11-23 04:48 | Vincent Lefevre | Section | => c99 |
| 2009-11-23 04:48 | Vincent Lefevre | Page Number | => 2489 |
| 2009-11-23 04:48 | Vincent Lefevre | Line Number | => 79574-79582 |
| 2009-11-23 16:21 | geoffclare | Note Added: 0000308 | |
| 2009-12-04 16:29 | geoffclare | Note Added: 0000322 | |
| 2009-12-10 16:12 | geoffclare | Interp Status | => Pending |
| 2009-12-10 16:12 | geoffclare | Final Accepted Text | => 0000187:0000322 |
| 2009-12-10 16:12 | geoffclare | Status | Under Review => Interpretation Required |
| 2009-12-10 16:12 | geoffclare | Resolution | Open => Accepted As Marked |
| 2009-12-10 16:14 | geoffclare | Note Edited: 0000322 | |
| 2010-02-12 06:38 | ajosey | Interp Status | Pending => Proposed |
| 2010-03-25 15:18 | ajosey | Interp Status | Proposed => Approved |
| 2010-09-24 14:27 | Don Cragun | Tag Attached: tc1-2008 | |
| 2013-04-16 13:06 | ajosey | Status | Interpretation Required => Closed |
