From 70ac1c4785fc1e158ab2349a962dba2526bf4fbc Mon Sep 17 00:00:00 2001 From: Alejandro Colomar Date: Mon, 5 Sep 2022 23:03:38 +0200 Subject: src.mk, All pages: Move man* to man/ The root of the repository is becoming a bit overpopulated and unorganized, due to the recent addition of more mandirs, and more informative and configuration files too. Let's create a specific mandir that contains the mandirs . Signed-off-by: Alejandro Colomar --- man/man3/readdir_r.3 | 145 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 145 insertions(+) create mode 100644 man/man3/readdir_r.3 (limited to 'man/man3/readdir_r.3') diff --git a/man/man3/readdir_r.3 b/man/man3/readdir_r.3 new file mode 100644 index 0000000000..2e25126411 --- /dev/null +++ b/man/man3/readdir_r.3 @@ -0,0 +1,145 @@ +.\" Copyright (C) 2008, 2016 Michael Kerrisk +.\" and Copyright (C) 2016 Florian Weimer +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.TH READDIR_R 3 2021-03-22 "Linux man-pages (unreleased)" +.SH NAME +readdir_r \- read a directory +.SH LIBRARY +Standard C library +.RI ( libc ", " \-lc ) +.SH SYNOPSIS +.nf +.B #include +.PP +.BI "[[deprecated]] int readdir_r(DIR *restrict " dirp , +.BI " struct dirent *restrict " entry , +.BI " struct dirent **restrict " result ); +.fi +.PP +.RS -4 +Feature Test Macro Requirements for glibc (see +.BR feature_test_macros (7)): +.RE +.PP +.BR readdir_r (): +.nf + _POSIX_C_SOURCE + || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE +.fi +.SH DESCRIPTION +This function is deprecated; use +.BR readdir (3) +instead. +.PP +The +.BR readdir_r () +function was invented as a reentrant version of +.BR readdir (3). +It reads the next directory entry from the directory stream +.IR dirp , +and returns it in the caller-allocated buffer pointed to by +.IR entry . +For details of the +.I dirent +structure, see +.BR readdir (3). +.PP +A pointer to the returned buffer is placed in +.IR *result ; +if the end of the directory stream was encountered, +then NULL is instead returned in +.IR *result . +.PP +It is recommended that applications use +.BR readdir (3) +instead of +.BR readdir_r (). +Furthermore, since version 2.24, glibc deprecates +.BR readdir_r (). +The reasons are as follows: +.IP * 3 +On systems where +.B NAME_MAX +is undefined, calling +.BR readdir_r () +may be unsafe because the interface does not allow the caller to specify +the length of the buffer used for the returned directory entry. +.IP * +On some systems, +.BR readdir_r () +can't read directory entries with very long names. +When the glibc implementation encounters such a name, +.BR readdir_r () +fails with the error +.B ENAMETOOLONG +.IR "after the final directory entry has been read" . +On some other systems, +.BR readdir_r () +may return a success status, but the returned +.I d_name +field may not be null terminated or may be truncated. +.IP * +In the current POSIX.1 specification (POSIX.1-2008), +.BR readdir (3) +is not required to be thread-safe. +However, in modern implementations (including the glibc implementation), +concurrent calls to +.BR readdir (3) +that specify different directory streams are thread-safe. +Therefore, the use of +.BR readdir_r () +is generally unnecessary in multithreaded programs. +In cases where multiple threads must read from the same directory stream, +using +.BR readdir (3) +with external synchronization is still preferable to the use of +.BR readdir_r (), +for the reasons given in the points above. +.IP * +It is expected that a future version of POSIX.1 +.\" FIXME . +.\" http://www.austingroupbugs.net/view.php?id=696 +will make +.BR readdir_r () +obsolete, and require that +.BR readdir (3) +be thread-safe when concurrently employed on different directory streams. +.SH RETURN VALUE +The +.BR readdir_r () +function returns 0 on success. +On error, it returns a positive error number (listed under ERRORS). +If the end of the directory stream is reached, +.BR readdir_r () +returns 0, and returns NULL in +.IR *result . +.SH ERRORS +.TP +.B EBADF +Invalid directory stream descriptor \fIdirp\fP. +.TP +.B ENAMETOOLONG +A directory entry whose name was too long to be read was encountered. +.SH ATTRIBUTES +For an explanation of the terms used in this section, see +.BR attributes (7). +.ad l +.nh +.TS +allbox; +lbx lb lb +l l l. +Interface Attribute Value +T{ +.BR readdir_r () +T} Thread safety MT-Safe +.TE +.hy +.ad +.sp 1 +.SH STANDARDS +POSIX.1-2001, POSIX.1-2008. +.SH SEE ALSO +.BR readdir (3) -- cgit 1.2.3-korg