The tmpnam() function is a special function which is declared inside “stdio.h” header file. It generates a different temporary file name each time it is called up to at least TMP_MAX names. Here TMP_MAX represents maximum number of different file names that can be produce by tmpnam() function. If it is called more than TMP_MAX times, the behavior is implementation dependent.Here, L_tmpnam define the size needed for an array of char to hold the result of tmpnam.
char *tmpnam(char *str) s : The character array to copy the file name. It generates and returns a valid temporary filename which does not exist. If str is null then it simply returns the tmp file name.
The file names are dependent on running machine, which can be anything. Example: /tmp/fileRTOA0m s260. s3ok. s5gg. etc
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