tmpnam() function in C

1

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.

Syntax :

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.
// C program to generate random temporary file names.
#include <stdio.h>
int main(void)
{
    // L_tmpnam declared in the stdio.h file.
    // L_tmpnam define length of the generated file name.
    char generate[L_tmpnam + 1]; // Add +1 for the null character.
    tmpnam(generate);
    puts(generate);
    return 0;
}

Output:

The file names are dependent on running machine, which can be anything.
Example: /tmp/fileRTOA0m
         \s260.
         \s3ok.
         \s5gg. etc

This article is contributed by Bishal Kumar Dubey. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

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