tmpfile - create a temporary file
The tmpfile() function opens a unique temporary file in binary read/write
(w+b) mode. The file will be automatically deleted when it is closed or the
The tmpfile() function returns a stream descriptor, or NULL if a unique
filename cannot be generated or the unique file cannot be opened. In the
latter case, errno is set to indicate the error.
- Search permission denied for directory in file's path prefix.
- Unable to generate a unique filename.
- The call was interrupted by a signal; see signal(7).
- The per-process limit on the number of open file descriptors has been
- The system-wide limit on the total number of open files has been
- There was no room in the directory to add the new filename.
- Read-only filesystem.
For an explanation of the terms used in this section, see attributes(7).
POSIX.1-2001, POSIX.1-2008, C89, C99, SVr4, 4.3BSD, SUSv2.
POSIX.1-2001 specifies: an error message may be written to stdout if the
stream cannot be opened.
The standard does not specify the directory that tmpfile()
will use. Glibc will try the path prefix P_tmpdir defined in
<stdio.h>, and if that fails the directory /tmp.
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