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diff --git a/man-pages-posix-2017/man3p/nftw.3p b/man-pages-posix-2017/man3p/nftw.3p new file mode 100644 index 0000000..baf46d2 --- /dev/null +++ b/man-pages-posix-2017/man3p/nftw.3p @@ -0,0 +1,360 @@ +'\" et +.TH NFTW "3P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual" +.\" +.SH PROLOG +This manual page is part of the POSIX Programmer's Manual. +The Linux implementation of this interface may differ (consult +the corresponding Linux manual page for details of Linux behavior), +or the interface may not be implemented on Linux. +.\" +.SH NAME +nftw +\(em walk a file tree +.SH SYNOPSIS +.LP +.nf +#include <ftw.h> +.P +int nftw(const char *\fIpath\fP, int (*\fIfn\fP)(const char *, + const struct stat *, int, struct FTW *), int \fIfd_limit\fP, int \fIflags\fP); +.fi +.SH DESCRIPTION +The +\fInftw\fR() +function shall recursively descend the directory hierarchy rooted in +.IR path . +The +\fInftw\fR() +function has a similar effect to +\fIftw\fR() +except that it takes an additional argument +.IR flags , +which is a bitwise-inclusive OR of zero or more of the following flags: +.IP FTW_CHDIR 12 +If set, +\fInftw\fR() +shall change the current working directory to each directory as it +reports files in that directory. If clear, +\fInftw\fR() +shall not change the current working directory. +.IP FTW_DEPTH 12 +If set, +\fInftw\fR() +shall report all files in a directory before reporting the directory +itself. If clear, +\fInftw\fR() +shall report any directory before reporting the files in that directory. +.IP FTW_MOUNT 12 +If set, +\fInftw\fR() +shall only report files in the same file system as +.IR path . +If clear, +\fInftw\fR() +shall report all files encountered during the walk. +.IP FTW_PHYS 12 +If set, +\fInftw\fR() +shall perform a physical walk and shall not follow symbolic links. +.P +If FTW_PHYS is clear and FTW_DEPTH is set, +\fInftw\fR() +shall follow links instead of reporting them, but shall not report any +directory that would be a descendant of itself. If FTW_PHYS is clear +and FTW_DEPTH is clear, +\fInftw\fR() +shall follow links instead of reporting them, but shall not report the +contents of any directory that would be a descendant of itself. +.P +At each file it encounters, +\fInftw\fR() +shall call the user-supplied function +.IR fn +with four arguments: +.IP " *" 4 +The first argument is the pathname of the object. +.IP " *" 4 +The second argument is a pointer to the +.BR stat +buffer containing information on the object, filled in as if +\fIfstatat\fR(), +\fIstat\fR(), +or +\fIlstat\fR() +had been called to retrieve the information. +.IP " *" 4 +The third argument is an integer giving additional information. Its +value is one of the following: +.RS 4 +.IP FTW_D 10 +The object is a directory. +.IP FTW_DNR 10 +The object is a directory that cannot be read. The +.IR fn +function shall not be called for any of its descendants. +.IP FTW_DP 10 +The object is a directory and subdirectories have been visited. (This +condition shall only occur if the FTW_DEPTH flag is included in +.IR flags .) +.IP FTW_F 10 +The object is a non-directory file. +.IP FTW_NS 10 +The +\fIstat\fR() +function failed on the object because of lack of appropriate +permission. The +.BR stat +buffer passed to +.IR fn +is undefined. Failure of +\fIstat\fR() +for any other reason is considered an error and +\fInftw\fR() +shall return \-1. +.IP FTW_SL 10 +The object is a symbolic link. (This condition shall only occur if the +FTW_PHYS flag is included in +.IR flags .) +.IP FTW_SLN 10 +The object is a symbolic link that does not name an existing file. +(This condition shall only occur if the FTW_PHYS flag is not included in +.IR flags .) +.RE +.IP " *" 4 +The fourth argument is a pointer to an +.BR FTW +structure. +The value of +.BR base +is the offset of the object's filename in the pathname passed as the +first argument to +.IR fn . +The value of +.BR level +indicates depth relative to the root of the walk, where the root level +is 0. +.P +The results are unspecified if the application-supplied +.IR fn +function does not preserve the current working directory. +.P +The argument +.IR fd_limit +sets the maximum number of file descriptors that shall be used by +\fInftw\fR() +while traversing the file tree. At most one file descriptor shall be +used for each directory level. +.P +The +\fInftw\fR() +function need not be thread-safe. +.SH "RETURN VALUE" +The +\fInftw\fR() +function shall continue until the first of the following conditions +occurs: +.IP " *" 4 +An invocation of +.IR fn +shall return a non-zero value, in which case +\fInftw\fR() +shall return that value. +.IP " *" 4 +The +\fInftw\fR() +function detects an error other than +.BR [EACCES] +(see FTW_DNR and FTW_NS above), +in which case +\fInftw\fR() +shall return \-1 and set +.IR errno +to indicate the error. +.IP " *" 4 +The tree is exhausted, in which case +\fInftw\fR() +shall return 0. +.SH ERRORS +The +\fInftw\fR() +function shall fail if: +.TP +.BR EACCES +Search permission is denied for any component of +.IR path +or read permission is denied for +.IR path , +or +.IR fn +returns \-1 and does not reset +.IR errno . +.TP +.BR ELOOP +A loop exists in symbolic links encountered during resolution of the +.IR path +argument. +.TP +.BR ENAMETOOLONG +.br +The length of a component of a pathname is longer than +{NAME_MAX}. +.TP +.BR ENOENT +A component of +.IR path +does not name an existing file or +.IR path +is an empty string. +.TP +.BR ENOTDIR +A component of +.IR path +names an existing file that is neither a directory nor a symbolic link +to a directory. +.TP +.BR EOVERFLOW +A field in the +.BR stat +structure cannot be represented correctly in the current programming +environment for one or more files found in the file hierarchy. +.P +The +\fInftw\fR() +function may fail if: +.TP +.BR ELOOP +More than +{SYMLOOP_MAX} +symbolic links were encountered during resolution of the +.IR path +argument. +.TP +.BR EMFILE +All file descriptors available to the process are currently open. +.TP +.BR ENAMETOOLONG +.br +The length of a pathname exceeds +{PATH_MAX}, +or pathname resolution of a symbolic link produced an intermediate +result with a length that exceeds +{PATH_MAX}. +.TP +.BR ENFILE +Too many files are currently open in the system. +.P +In addition, +.IR errno +may be set if the function pointed to by +.IR fn +causes +.IR errno +to be set. +.LP +.IR "The following sections are informative." +.SH EXAMPLES +The following program traverses the directory tree under the path named +in its first command-line argument, or under the current directory if +no argument is supplied. It displays various information about each +file. The second command-line argument can be used to specify characters +that control the value assigned to the +.IR flags +argument when calling +\fInftw\fR(). +.sp +.RS 4 +.nf + +#include <ftw.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <stdint.h> +.P +static int +display_info(const char *fpath, const struct stat *sb, + int tflag, struct FTW *ftwbuf) +{ + printf("%-3s %2d %7jd %-40s %d %s\en", + (tflag == FTW_D) ? "d" : (tflag == FTW_DNR) ? "dnr" : + (tflag == FTW_DP) ? "dp" : (tflag == FTW_F) ? + (S_ISBLK(sb->st_mode) ? "f b" : + S_ISCHR(sb->st_mode) ? "f c" : + S_ISFIFO(sb->st_mode) ? "f p" : + S_ISREG(sb->st_mode) ? "f r" : + S_ISSOCK(sb->st_mode) ? "f s" : "f ?") : + (tflag == FTW_NS) ? "ns" : (tflag == FTW_SL) ? "sl" : + (tflag == FTW_SLN) ? "sln" : "?", + ftwbuf->level, (intmax_t) sb->st_size, + fpath, ftwbuf->base, fpath + ftwbuf->base); + return 0; /* To tell nftw() to continue */ +} +.P +int +main(int argc, char *argv[]) +{ + int flags = 0; +.P + if (argc > 2 && strchr(argv[2], \(aqd\(aq) != NULL) + flags |= FTW_DEPTH; + if (argc > 2 && strchr(argv[2], \(aqp\(aq) != NULL) + flags |= FTW_PHYS; +.P + if (nftw((argc < 2) ? "." : argv[1], display_info, 20, flags) == -1) + { + perror("nftw"); + exit(EXIT_FAILURE); + } +.P + exit(EXIT_SUCCESS); +} +.fi +.P +.RE +.SH "APPLICATION USAGE" +The +\fInftw\fR() +function may allocate dynamic storage during its operation. If +\fInftw\fR() +is forcibly terminated, such as by +\fIlongjmp\fR() +or +\fIsiglongjmp\fR() +being executed by the function pointed to by +.IR fn +or an interrupt routine, +\fInftw\fR() +does not have a chance to free that storage, so it remains permanently +allocated. A safe way to handle interrupts is to store the fact that an +interrupt has occurred, and arrange to have the function pointed to by +.IR fn +return a non-zero value at its next invocation. +.SH RATIONALE +None. +.SH "FUTURE DIRECTIONS" +None. +.SH "SEE ALSO" +.IR "\fIfdopendir\fR\^(\|)", +.IR "\fIfstatat\fR\^(\|)", +.IR "\fIreaddir\fR\^(\|)" +.P +The Base Definitions volume of POSIX.1\(hy2017, +.IR "\fB<ftw.h>\fP" +.\" +.SH COPYRIGHT +Portions of this text are reprinted and reproduced in electronic form +from IEEE Std 1003.1-2017, Standard for Information Technology +-- Portable Operating System Interface (POSIX), The Open Group Base +Specifications Issue 7, 2018 Edition, +Copyright (C) 2018 by the Institute of +Electrical and Electronics Engineers, Inc and The Open Group. +In the event of any discrepancy between this version and the original IEEE and +The Open Group Standard, the original IEEE and The Open Group Standard +is the referee document. The original Standard can be obtained online at +http://www.opengroup.org/unix/online.html . +.PP +Any typographical or formatting errors that appear +in this page are most likely +to have been introduced during the conversion of the source files to +man page format. To report such errors, see +https://www.kernel.org/doc/man-pages/reporting_bugs.html . |