Date: Sun, 3 Jan 2010 01:04:51 GMT From: Kevin Barry <ta0kira@users.berlios.de> To: freebsd-gnats-submit@FreeBSD.org Subject: standards/142255: scandir prototype in dirent.h isn't compliant with POSIX 2008 Message-ID: <201001030104.o0314pUt008675@www.freebsd.org> Resent-Message-ID: <201001030110.o031A2Tb006542@freefall.freebsd.org>
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>Number: 142255
>Category: standards
>Synopsis: scandir prototype in dirent.h isn't compliant with POSIX 2008
>Confidential: no
>Severity: non-critical
>Priority: medium
>Responsible: freebsd-standards
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Sun Jan 03 01:10:01 UTC 2010
>Closed-Date:
>Last-Modified:
>Originator: Kevin Barry
>Release: 8.0-RELEASE
>Organization:
>Environment:
FreeBSD kpbarry.student.cwru.edu 8.0-RELEASE FreeBSD 8.0-RELEASE #0: Sat Nov 21 15:02:08 UTC 2009 root@mason.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC amd64
>Description:
The POSIX standard declares 'scandir' as follows, copied directly:
int scandir(const char *dir, struct dirent ***namelist,
int (*sel)(const struct dirent *),
int (*compar)(const struct dirent **, const struct dirent **));
The problem in FreeBSD is the 'sel' argument, which is a pointer to a function taking a 'struct dirent *' without the 'const'. This is a problem when trying to write POSIX-portable code. In C I only receive a warning when trying to pass a function pointer of the correct type, however, in C++ this is an error. An argument cast isn't the solution because I still need my code to work in Linux; therefore, I've had to separate the call to 'scandir' in a C file, separate from the C++ code. Another solution is to C-cast a pointer to 'scandir' and dereference it, which I might consider. Thanks!
Kevin Barry
>How-To-Repeat:
#include <dirent.h>
static int sel(const struct dirent*)
{ return 1; }
int main()
{ scandir(0, 0, &sel, 0); }
Compile the above with g++.
>Fix:
Change the prototype of 'scandir' in dirent.h.
>Release-Note:
>Audit-Trail:
>Unformatted:
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