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| author | Alejandro Colomar <alx.manpages@gmail.com> | 2022-09-05 23:03:38 +0200 |
|---|---|---|
| committer | Alejandro Colomar <alx.manpages@gmail.com> | 2022-09-05 23:03:47 +0200 |
| commit | 70ac1c4785fc1e158ab2349a962dba2526bf4fbc (patch) | |
| tree | bff270e2496dd284bccfc1271b43946f5d225224 /man/man3/tempnam.3 | |
| parent | 5423a6f86b2b920a5f3e8cf8d759b513050f2d33 (diff) | |
| download | man-pages-70ac1c4785fc1e158ab2349a962dba2526bf4fbc.tar.gz | |
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 <man/> that contains the mandirs <man[1-8]*>.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Diffstat (limited to 'man/man3/tempnam.3')
| -rw-r--r-- | man/man3/tempnam.3 | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/man/man3/tempnam.3 b/man/man3/tempnam.3 new file mode 100644 index 0000000000..faeb5ca090 --- /dev/null +++ b/man/man3/tempnam.3 @@ -0,0 +1,177 @@ +.\" Copyright (c) 1999 Andries Brouwer (aeb@cwi.nl) +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.TH TEMPNAM 3 2021-03-22 "Linux man-pages (unreleased)" +.SH NAME +tempnam \- create a name for a temporary file +.SH LIBRARY +Standard C library +.RI ( libc ", " \-lc ) +.SH SYNOPSIS +.nf +.B #include <stdio.h> +.PP +.BI "char *tempnam(const char *" dir ", const char *" pfx ); +.fi +.PP +.RS -4 +Feature Test Macro Requirements for glibc (see +.BR feature_test_macros (7)): +.RE +.PP +.BR tempnam (): +.nf + Since glibc 2.19: + _DEFAULT_SOURCE + Glibc 2.19 and earlier: + _BSD_SOURCE || _SVID_SOURCE +.fi +.SH DESCRIPTION +.I "Never use this function." +Use +.BR mkstemp (3) +or +.BR tmpfile (3) +instead. +.PP +The +.BR tempnam () +function returns a pointer to a string that is a valid filename, +and such that a file with this name did not exist when +.BR tempnam () +checked. +The filename suffix of the pathname generated will start with +.I pfx +in case +.I pfx +is a non-NULL string of at most five bytes. +The directory prefix part of the pathname generated is required to +be "appropriate" (often that at least implies writable). +.PP +Attempts to find an appropriate directory go through the following +steps: +.TP 3 +a) +In case the environment variable +.B TMPDIR +exists and +contains the name of an appropriate directory, that is used. +.TP +b) +Otherwise, if the +.I dir +argument is non-NULL and appropriate, it is used. +.TP +c) +Otherwise, +.I P_tmpdir +(as defined in +.IR <stdio.h> ) +is used when appropriate. +.TP +d) +Finally an implementation-defined directory may be used. +.PP +The string returned by +.BR tempnam () +is allocated using +.BR malloc (3) +and hence should be freed by +.BR free (3). +.SH RETURN VALUE +On success, the +.BR tempnam () +function returns a pointer to a unique temporary filename. +It returns NULL if a unique name cannot be generated, with +.I errno +set to indicate the error. +.SH ERRORS +.TP +.B ENOMEM +Allocation of storage failed. +.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 tempnam () +T} Thread safety MT-Safe env +.TE +.hy +.ad +.sp 1 +.SH STANDARDS +SVr4, 4.3BSD, POSIX.1-2001. +POSIX.1-2008 marks +.BR tempnam () +as obsolete. +.SH NOTES +Although +.BR tempnam () +generates names that are difficult to guess, +it is nevertheless possible that between the time that +.BR tempnam () +returns a pathname, and the time that the program opens it, +another program might create that pathname using +.BR open (2), +or create it as a symbolic link. +This can lead to security holes. +To avoid such possibilities, use the +.BR open (2) +.B O_EXCL +flag to open the pathname. +Or better yet, use +.BR mkstemp (3) +or +.BR tmpfile (3). +.PP +SUSv2 does not mention the use of +.BR TMPDIR ; +glibc will use it only +when the program is not set-user-ID. +On SVr4, the directory used under \fBd)\fP is +.I /tmp +(and this is what glibc does). +.PP +Because it dynamically allocates memory used to return the pathname, +.BR tempnam () +is reentrant, and thus thread safe, unlike +.BR tmpnam (3). +.PP +The +.BR tempnam () +function generates a different string each time it is called, +up to +.B TMP_MAX +(defined in +.IR <stdio.h> ) +times. +If it is called more than +.B TMP_MAX +times, +the behavior is implementation defined. +.PP +.BR tempnam () +uses at most the first five bytes from +.IR pfx . +.PP +The glibc implementation of +.BR tempnam () +fails with the error +.B EEXIST +upon failure to find a unique name. +.SH BUGS +The precise meaning of "appropriate" is undefined; +it is unspecified how accessibility of a directory is determined. +.SH SEE ALSO +.BR mkstemp (3), +.BR mktemp (3), +.BR tmpfile (3), +.BR tmpnam (3) |