tempnam

Synopsis

#include <stdio.h>

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

Status

Implemented

Conformance

IEEE Std 1003.1-2017

Description

The tempnam() function shall generate a path name 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 (/var/tmp) shall be used. If that directory is not accessible, the root directory (/) is 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. Only the first five bytes of a longer string are used. If pfx is a null pointer, the prefix file is used.

The generated name ends with six characters from the portable filename character set chosen at random, and doesn’t name an existing file at the time of the call. Up to {TMP_MAX} names are generated before tempnam() gives up.

Return value

Upon successful completion, tempnam() shall allocate space for a string, put the generated path name in that space, and return a pointer to it. The pointer shall be suitable for use in a subsequent call to free(). Otherwise, it shall return a null pointer and set errno to indicate the error.

Errors

The tempnam() function shall fail if:

• ENOMEM - Insufficient storage space is available.

POSIX deviations

No POSIX deviations discovered.