TEMPNAM

TEMPNAM

NAME SYNOPSIS DESCRIPTION RETURN VALUE ERRORS NOTES BUGS CONFORMING TO SEE ALSO

NAME

tempnam - create a name for a temporary file

SYNOPSIS

#include dir, const char *pfx);

DESCRIPTION

The tempnam() function returns a pointer to a string that is a valid filename, and such that a file with this name did not exist when tempnam() checked. The filename suffix of the pathname generated will start with pfx in case pfx is a non-NULL string of at most five bytes. The directory prefix part of the pathname generated is required to be `appropriate' (often that at least implies writable). Attempts to find an appropriate directory go through the following steps: (i) In case the environment variable TMPDIR exists and contains the name of an appropriate directory, that is used. (ii) Otherwise, if the dir argument is non-NULL and appropriate, it is used. (iii) Otherwise, P_tmpdir (as defined in ) is used when appropriate. (iv) Finally an implementation-defined directory may be used.

RETURN VALUE

The tempnam() function returns a pointer to a unique temporary filename, or NULL if a unique name cannot be generated.

ERRORS

ENOMEM

Allocation of storage failed.

NOTES

SUSv2 does not mention the use of TMPDIR; glibc will use it only when the program is not suid. SVID2 specifies that the directory used under (iv) is /tmp. SVID2 specifies that the string returned by tempnam() was allocated using malloc(3) and hence can be freed by free(3).

The tempnam() function generates a different string each time it is called, up to TMP_MAX (defined in ) times. If it is called more than TMP_MAX times, the behaviour is implementation defined.

In case the pfx argument has length larger than five, glibc will use the first five bytes. Upon failure to find a unique name, glibc will return EEXIST.

BUGS

The precise meaning of `appropriate' is undefined; it is unspecified how accessibility of a directory is determined. Never use this function. Use tmpfile(3) instead.

CONFORMING TO

SVID 2, BSD 4.3

SEE ALSO

mktemp(3), mkstemp(3), tmpfile(3), tmpnam(3)