Tmpfile

In computing, tmpfile is an ISO C/POSIX function for creating a temporary file, a computer file which ceases to exist when the program, which opened the file, closes it or terminates. [http://www.opengroup.org/onlinepubs/009695399/functions/tmpfile.html tmpfile] by OpenGroup] [ [http://www.gnu.org/software/libtool/manual/libc/Temporary-Files.html Temporary Files] by GNU C Library] [ [http://www.hmug.org/man/3/tmpfile.php tmpfile] by HMUG]

Usage

Inclusion

; C#include ; C++#include

Declaration

FILE* tmpfile(void);

emantics

The function tmpfile reports a pointer to a valid file stream on success; on failure, it returns NULL.

Error conditions

In addition to returning NULL, tmpfile sets errno on failure. The permissible values of errno, if tmpfile fails, are:
*EINTR - if a signal was caught during the execution of tmpfile.
*EMFILE - if the maximum number of file descriptors and/or the maximum number of file streams has been reached (in the process).
*ENFILE - if the maximum allowable number of files is currently open (in the system).
*ENOSPC - if there is no space in the file system for creating the temporary file.
*EOVERFLOW - if the file is a regular file and the size of the file cannot be represented correctly in an object of type off_t.
*ENOMEM - if there is insufficient memory for allocating the file stream.

Caveats

The tmpfile function is susceptible to a number of security vulnerabilities; use the non-portable mkstemp (UNIX) or tmpfile_s (Windows) functions, instead, to avoid these issues. [ [https://buildsecurityin.us-cert.gov/daisy/bsi-rules/home/g1/861-BSI.html TMPNAM-TMPFILE Vulnerability] by Build Security In] [https://www.securecoding.cert.org/confluence/display/seccode/VOID+FI039-C.+Create+temporary+files+securely VOID FI039-C. Create temporary files securely] by CERT]

References

ee also

*mkstemp
*fopen
*fclose
*stdio.h