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Diffstat (limited to 'man3/tmpnam.3')
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diff --git a/man3/tmpnam.3 b/man3/tmpnam.3 new file mode 100644 index 0000000..5798faa --- /dev/null +++ b/man3/tmpnam.3 @@ -0,0 +1,169 @@ +'\" t +.\" Copyright (c) 1999 Andries Brouwer (aeb@cwi.nl) +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.\" 2003-11-15, aeb, added tmpnam_r +.\" +.TH tmpnam 3 2023-07-20 "Linux man-pages 6.05.01" +.SH NAME +tmpnam, tmpnam_r \- create a name for a temporary file +.SH LIBRARY +Standard C library +.RI ( libc ", " \-lc ) +.SH SYNOPSIS +.nf +.B #include <stdio.h> +.PP +.BI "[[deprecated]] char *tmpnam(char *" s ); +.BI "[[deprecated]] char *tmpnam_r(char *" s ); +.fi +.PP +.RS -4 +Feature Test Macro Requirements for glibc (see +.BR feature_test_macros (7)): +.RE +.PP +.BR tmpnam_r () +.nf + Since glibc 2.19: + _DEFAULT_SOURCE + Up to and including glibc 2.19: + _BSD_SOURCE || _SVID_SOURCE +.fi +.SH DESCRIPTION +.B Note: +avoid using these functions; use +.BR mkstemp (3) +or +.BR tmpfile (3) +instead. +.PP +The +.BR tmpnam () +function returns a pointer to a string that is a valid filename, +and such that a file with this name did not exist at some point +in time, so that naive programmers may think it +a suitable name for a temporary file. +If the argument +.I s +is NULL, this name is generated in an internal static buffer +and may be overwritten by the next call to +.BR tmpnam (). +If +.I s +is not NULL, the name is copied to the character array (of length +at least +.IR L_tmpnam ) +pointed to by +.I s +and the value +.I s +is returned in case of success. +.PP +The created pathname has a directory prefix +.IR P_tmpdir . +(Both +.I L_tmpnam +and +.I P_tmpdir +are defined in +.IR <stdio.h> , +just like the +.B TMP_MAX +mentioned below.) +.PP +The +.BR tmpnam_r () +function performs the same task as +.BR tmpnam (), +but returns NULL (to indicate an error) if +.I s +is NULL. +.SH RETURN VALUE +These functions return a pointer to a unique temporary +filename, or NULL if a unique name cannot be generated. +.SH ERRORS +No errors are defined. +.SH ATTRIBUTES +For an explanation of the terms used in this section, see +.BR attributes (7). +.TS +allbox; +lbx lb lb +l l l. +Interface Attribute Value +T{ +.na +.nh +.BR tmpnam () +T} Thread safety MT-Unsafe race:tmpnam/!s +T{ +.na +.nh +.BR tmpnam_r () +T} Thread safety MT-Safe +.TE +.sp 1 +.SH STANDARDS +.TP +.BR tmpnam () +C11, POSIX.1-2008. +.TP +.BR tmpnam_r () +None. +.SH HISTORY +.TP +.BR tmpnam () +SVr4, 4.3BSD, C89, POSIX.1-2001. +Obsolete in POSIX.1-2008. +.TP +.BR tmpnam_r () +Solaris. +.SH NOTES +The +.BR tmpnam () +function generates a different string each time it is called, +up to +.B TMP_MAX +times. +If it is called more than +.B TMP_MAX +times, +the behavior is implementation defined. +.PP +Although these functions generate names that are difficult to guess, +it is nevertheless possible that between the time that +the pathname is returned 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 +Portable applications that use threads cannot call +.BR tmpnam () +with a NULL argument if either +.B _POSIX_THREADS +or +.B _POSIX_THREAD_SAFE_FUNCTIONS +is defined. +.SH BUGS +Never use these functions. +Use +.BR mkstemp (3) +or +.BR tmpfile (3) +instead. +.SH SEE ALSO +.BR mkstemp (3), +.BR mktemp (3), +.BR tempnam (3), +.BR tmpfile (3) |