dlopen.3: Clarify that constructors are called only when library is first loaded

[thirdparty/man-pages.git] / man3 / getcwd.3

diff --git a/man3/getcwd.3 b/man3/getcwd.3
index cb5b11bbcc5d3d71de04f610083f9fc200f46ecd..c8a691b4adf181bdbef07ce0a637f9ae116b5053 100644 (file)
--- a/man3/getcwd.3
+++ b/man3/getcwd.3
@@ -266,10 +266,29 @@ to return is usually a faster and more reliable alternative when sufficiently
 many file descriptors are available, especially on platforms other than Linux.
 .\"
 .SS C library/kernel differences
+On Linux, the kernel provides a
+.BR getcwd ()
+system call, which the functions described in this page will use if possible.
+The system call takes the same arguments as the library function
+of the same name, but is limited to returning at most
+.BR PATH_MAX
+bytes.
+(Before Linux 3.12,
+.\" commit 3272c544da48f8915a0e34189182aed029bd0f2b
+the limit on the size of the returned pathname was the system page size.
+On many architectures,
+.BR PATH_MAX
+and the system page size are both 4096 bytes,
+but a few architectures have a larger page size.)
+If the length of the pathname of the current working directory
+exceeds this limit, then the system call fails with the error
+.BR ENAMETOOLONG .
+In this case, the library functions fall back to
+a (slower) alternative implementation that returns the full pathname.
 .PP
 Following a change in Linux 2.6.36,
 .\" commit 8df9d1a4142311c084ffeeacb67cd34d190eff74
-the path returned by the
+the pathname returned by the
 .BR getcwd ()
 system call will be prefixed with the string "(unreachable)"
 if the current directory is not below the root directory of the current
@@ -278,21 +297,21 @@ process (e.g., because the process set a new filesystem root using
 without changing its current directory into the new root).
 Such behavior can also be caused by an unprivileged user by changing
 the current directory into another mount namespace.
-When dealing with paths from untrusted sources, callers of the
+When dealing with pathname from untrusted sources, callers of the
 functions described in this page
-should consider checking whether the returned path starts
+should consider checking whether the returned pathname starts
 with '/' or '(' to avoid misinterpreting an unreachable path
-as a relative path.
+as a relative pathname.
 .SH BUGS
 Since the Linux 2.6.36 change that added "(unreachable)" in the
 circumstances described above, the glibc implementation of
 .BR getcwd ()
-has failed to conform to POSIX and returned a relative path when the API
-contract requires an absolute path.
+has failed to conform to POSIX and returned a relative pathname when the API
+contract requires an absolute pathname.
 With glibc 2.27 onwards this is corrected;
 calling
 .BR getcwd ()
-from such a path will now result in failure with
+from such a pathname will now result in failure with
 .BR ENOENT .
 .SH SEE ALSO
 .BR pwd (1),