mkstemp, mkostemp, mkstemps, mkostemps - create a unique temporary file
#include <stdlib.h>
int mkstemp(char *template);
int mkostemp(char *template, int flags);
int mkstemps(char *template, int suffixlen);
int mkostemps(char *template, int suffixlen, int flags);Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
The mkstemp() function generates a unique temporary filename from template, creates and opens the file, and returns an open file descriptor for the file.
The last six characters of template must be "XXXXXX" and these are replaced with a string that makes the filename unique. Since it will be modified, template must not be a string constant, but should be declared as a character array.
The file is created with permissions 0600, that is, read plus write for owner only. The returned file descriptor provides both read and write access to the file. The file is opened with the open(2) O_EXCL flag, guaranteeing that the caller is the process that creates the file.
The mkostemp() function is like mkstemp(), with the difference that the following bits—with the same meaning as for open(2)—may be specified in flags: O_APPEND, O_CLOEXEC, and O_SYNC. Note that when creating the file, mkostemp() includes the values O_RDWR, O_CREAT, and O_EXCL in the flags argument given to open(2); including these values in the flags argument given to mkostemp() is unnecessary, and produces errors on some systems.
The mkstemps() function is like mkstemp(), except that the string in template contains a suffix of suffixlen characters. Thus, template is of the form prefixXXXXXXsuffix, and the string XXXXXX is modified as for mkstemp().
The mkostemps() function is to mkstemps() as mkostemp() is to mkstemp().
On success, these functions return the file descriptor of the temporary file. On error, -1 is returned, and errno is set appropriately.