tmpfile() function in C

In C Programming Language, the tmpfile() function is used to produce/create a temporary file.

• tmpfile() function is defined in the “stdio.h” header file.
• The created temporary file will automatically be deleted after the termination of program.
• It opens file in binary update mode i.e., wb+ mode.
• The syntax of tmpfile() function is:

  FILE *tmpfile(void) 

• The tmpfile() function always returns a pointer after the creation of file to the temporary file. If by chance temporary file can not be created, then the tmpfile() function returns NULL pointer.

// C program to demonstrate working of tmpfile()
#include <stdio.h>
int main()
{
    char str[] = "Hello GeeksforGeeks";
    int i = 0;

    FILE* tmp = tmpfile();
    if (tmp == NULL)
    {
        puts("Unable to create temp file");
        return 0;
    }

    puts("Temporary file is created\n");
    while (str[i] != '\0')
    {
        fputc(str[i], tmp);
        i++;
    }

    // rewind() function sets the file pointer
    // at the beginning of the stream.
    rewind(tmp);

    while (!feof(tmp))
        putchar(fgetc(tmp));
}

Output:

Temporary file is created
Hello GeeksforGeeks