TMPFILE(3) Linux Programmer's Manual TMPFILE(3) NAME tmpfile - create a temporary file SYNOPSIS #include <stdio.h> FILE *tmpfile(void); DESCRIPTION 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 program terminates. RETURN VALUE 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. ERRORS EACCES Search permission denied for directory in file's path prefix. EEXIST Unable to generate a unique filename. EINTR The call was interrupted by a signal; see signal(7). EMFILE The per-process limit on the number of open file descriptors has been reached. ENFILE The system-wide limit on the total number of open files has been reached. ENOSPC There was no room in the directory to add the new filename. EROFS Read-only filesystem. ATTRIBUTES For an explanation of the terms used in this section, see attributes(7). ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┬───────────────┬─────────┐ │Interface │ Attribute │ Value │ ├──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┼───────────────┼─────────┤ │tmpfile() │ Thread safety │ MT-Safe │ └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┴───────────────┴─────────┘ CONFORMING TO POSIX.1-2001, POSIX.1-2008, C89, C99, SVr4, 4.3BSD, SUSv2. NOTES 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, then the directory /tmp. SEE ALSO exit(3), mkstemp(3), mktemp(3), tempnam(3), tmpnam(3) 2021-03-22 TMPFILE(3)