On 2025-10-18 13:50, Marco Atzeri via Cygwin wrote:
from
https://pubs.opengroup.org/onlinepubs/9799919799/functions/mkdtemp.html
Issue 7
Austin Group Interpretation 1003.1-2001 #143 is applied.
SD5-XSH-ERN-168 is applied, clarifying file permissions upon creation.
The mkstemp() function is moved from the XSI option to the Base.
I would expect --std=c++-20 should be enough, but
currently --std=gnu++-20 is required to build latest
version of libheif
"Issue 8
Austin Group Defect 251 is applied, encouraging implementations to disallow the
creation of filenames containing any bytes that have the encoded value of a
<newline> character.
Austin Group Defects 411, 1318, and 1350 are applied, adding mkostemp().
Austin Group Defect 652 is applied, adding the [EINVAL] error for mkstemp().
Austin Group Defect 1734 is applied, replacing the error conditions specified
only for mkdtemp() with a reference to mkdir()."
Those functions are not in Standard C or draft C 203Y (below);
mkstemp is POSIX from 200112 and no longer in XSI;
mkostemp/s requires || __POSIX_VISIBLE >= 202405 (from _POSIX_C_SOURCE >=
202405L) - in newlib, and also in glibc below;
all require POSIX features enabled by some definition;
from Linux 6.15 mkstemp(3):
"Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
mkstemp():
_XOPEN_SOURCE >= 500
|| /* glibc >= 2.12: */ _POSIX_C_SOURCE >= 200809L
|| /* glibc <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE
mkostemp():
_GNU_SOURCE"
q
$ grep -HwC1 'mk\(d\|os\|s\)temp' ~/src/standard-docs/C/N3220-C2023-FDIS.txt
$ grep -HwC1 'mk\(d\|os\|s\)temp' ~/src/standard-docs/C/N3685-C203Y-WD.txt
$ grep -HwC1 'mk\(d\|os\|s\)temp' /usr/include/stdlib.h
/usr/include/stdlib.h-#if __BSD_VISIBLE || __POSIX_VISIBLE >= 200809
/usr/include/stdlib.h:char * mkdtemp (char *);
/usr/include/stdlib.h-#endif
/usr/include/stdlib.h-#if __GNU_VISIBLE
/usr/include/stdlib.h:int mkostemp (char *, int);
/usr/include/stdlib.h-int mkostemps (char *, int, int);
--
/usr/include/stdlib.h-#if __MISC_VISIBLE || __POSIX_VISIBLE >= 200112 ||
__XSI_VISIBLE >= 4
/usr/include/stdlib.h:int mkstemp (char *);
/usr/include/stdlib.h-#endif
[I use C 203Y because there is almost no chance another C Standard will be
released this decade; especially as current POSIX has not yet been adopted by
ISO, as it has to be passed through the IEEE Partner Standards Development Org
(PSDO) FDIS "fast-track" process with Edition 2 ballot close on 2026-01-24.]
--
Take care. Thanks, Brian Inglis Calgary, Alberta, Canada
La perfection est atteinte Perfection is achieved
non pas lorsqu'il n'y a plus rien à ajouter not when there is no more to add
mais lorsqu'il n'y a plus rien à retrancher but when there is no more to cut
-- Antoine de Saint-Exupéry
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