The Single UNIX ® Specification, Version 2
Copyright © 1997 The Open Group


tempnam - create a name for a temporary file


#include <stdio.h>

char *tempnam(const char *dir, const char *pfx);


The tempnam() function generates a pathname that may be used for a temporary file.

The tempnam() function allows the user to control the choice of a directory. The dir argument points to the name of the directory in which the file is to be created. If dir is a null pointer or points to a string which is not a name for an appropriate directory, the path prefix defined as {P_tmpdir} in the <stdio.h> header is used. If that directory is not accessible, an implementation-dependent directory may be used.

Many applications prefer their temporary files to have certain initial letter sequences in their names. The pfx argument should be used for this. This argument may be a null pointer or point to a string of up to five bytes to be used as the beginning of the filename.

Some implementations of tempnam() may use tmpnam() internally. On such implementations, if called more than {TMP_MAX} times in a single process, the behaviour is implementation-dependent.


Upon successful completion, tempnam() allocates space for a string, puts the generated pathname in that space and returns a pointer to it. The pointer is suitable for use in a subsequent call to free(). Otherwise it returns a null pointer and sets errno to indicate the error.


The tempnam() function will fail if:
Insufficient storage space is available.




This function only creates pathnames. It is the application's responsibility to create and remove the files. Between the time a pathname is created and the file is opened, it is possible for some other process to create a file with the same name. Applications may find tmpfile() more useful.




fopen(), free(), open(), tmpfile(), tmpnam(), unlink(), <stdio.h>.


Derived from Issue 1 of the SVID.

UNIX ® is a registered Trademark of The Open Group.
Copyright © 1997 The Open Group
[ Main Index | XSH | XCU | XBD | XCURSES | XNS ]