diff options
Diffstat (limited to 'hurd/porting/guidelines.mdwn')
| -rw-r--r-- | hurd/porting/guidelines.mdwn | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/hurd/porting/guidelines.mdwn b/hurd/porting/guidelines.mdwn index d132f516..624f7fd5 100644 --- a/hurd/porting/guidelines.mdwn +++ b/hurd/porting/guidelines.mdwn @@ -132,7 +132,7 @@ If you get Bad File Descriptor error when trying to read from a file (or accessi <http://pubs.opengroup.org/onlinepubs/009695399/basedefs/limits.h.html> -Also see <https://eklitzke.org/path-max-is-tricky> +Also see <https://eklitzke.org/path-max-is-tricky> and <https://insanecoding.blogspot.com/2007/11/pathmax-simply-isnt.html> Every unconditionalized use of `PATH_MAX`, `MAX_PATH` or `MAXPATHLEN` is a POSIX incompatibility. If there is no upper limit on the length of a path (as its the case for GNU), this symbol is not defined in any header file. Instead, you need to either use a different implementation that does not rely on the length of a string or use `sysconf()` to query the length at runtime. If `sysconf()` returns -1, you have to use `realloc()` to allocate the needed memory dynamically. Usually it is thus simpler to just use dynamic allocation. Sometimes the amount is actually known. Else, a geometrically growing loop can be used: for instance, see [Pulseaudio patch](http://bugs.debian.org/cgi-bin/bugreport.cgi?msg=5;filename=patch-pulse;att=1;bug=522100). Note that in some cases there are GNU extensions that just work fine: when the `__GLIBC__` macro is defined, `getcwd()` calls can be just replaced by `get_current_dir_name()` calls. @@ -142,10 +142,10 @@ for a potential corresponding `PATH_MAX` macro. They are not a replacement for Note 2: Yes, some POSIX functions such as `realpath()` actually assume that `PATH_MAX` is defined. This is a bug of the POSIX standard, which got fixed in -POSIX 2001, in which one can simply pass `NULL` to get a dynamically +POSIX 2008, in which one can simply pass `NULL` to get a dynamically allocated buffer. One can thus use: - #if _POSIX_VERSION >= 200112 || defined(__GLIBC__) + #if _POSIX_VERSION >= 200809 || defined(__GLIBC__) char *path = realpath(orig, NULL); #else char path[PATH_MATH]; |