# tmpfile

## PROLOG



           This manual page is part of the POSIX Programmer's Manual.  The
           Linux implementation of this interface may differ (consult the
           corresponding Linux manual page for details of Linux behavior), or
           the interface may not be implemented on Linux.
    


## NAME



           tmpfile — create a temporary file
    


## SYNOPSIS



           #include <stdio.h>
    
           FILE *tmpfile(void);
    


## DESCRIPTION



           The functionality described on this reference page is aligned with
           the ISO C standard. Any conflict between the requirements
           described here and the ISO C standard is unintentional. This
           volume of POSIX.1‐2017 defers to the ISO C standard.
    
           The _tmpfile_() function shall create a temporary file and open a
           corresponding stream. The file shall be automatically deleted when
           all references to the file are closed. The file shall be opened as
           in _fopen_() for update (_wb_ +), except that implementations may
           restrict the permissions, either by clearing the file mode bits or
           setting them to the value S_IRUSR | S_IWUSR.
    
           In some implementations, a permanent file may be left behind if
           the process calling _tmpfile_() is killed while it is processing a
           call to _tmpfile_().
    
           An error message may be written to standard error if the stream
           cannot be opened.
    


## RETURN VALUE



           Upon successful completion, _tmpfile_() shall return a pointer to
           the stream of the file that is created.  Otherwise, it shall
           return a null pointer and set _errno_ to indicate the error.
    


## ERRORS



           The _tmpfile_() function shall fail if:
    
           **EINTR** A signal was caught during _tmpfile_().
    
           **EMFILE** All file descriptors available to the process are currently
                  open.
    
           **EMFILE**{STREAM_MAX} streams are currently open in the calling
                  process.
    
           **ENFILE** The maximum allowable number of files is currently open in
                  the system.
    
           **ENOSPC** The directory or file system which would contain the new
                  file cannot be expanded.
    
           **EOVERFLOW**
                  The file is a regular file and the size of the file cannot
                  be represented correctly in an object of type **off_t**.
    
           The _tmpfile_() function may fail if:
    
           **EMFILE**{FOPEN_MAX} streams are currently open in the calling
                  process.
    
           **ENOMEM** Insufficient storage space is available.
    
           _The following sections are informative._
    


## EXAMPLES



       **Creating a Temporary File**
           The following example creates a temporary file for update, and
           returns a pointer to a stream for the created file in the _fp_
           variable.
    
               #include <stdio.h>
               ...
               FILE *fp;
    
               fp = tmpfile ();
    


## APPLICATION USAGE



           It should be possible to open at least {TMP_MAX} temporary files
           during the lifetime of the program (this limit may be shared with
           _tmpnam_()) and there should be no limit on the number
           simultaneously open other than this limit and any limit on the
           number of open file descriptors or streams ({OPEN_MAX},
           {FOPEN_MAX}, {STREAM_MAX}).
    


## RATIONALE



           None.
    


## FUTURE DIRECTIONS



           None.
    


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