create text file in /tmp folder in Linux using c language - c

Question

By using c language I need to create a text file in /tmp directory, but I don't know how to do this. Is there anyone who knows how to create a text file in /tmp folder?

Answer 1

There's mkstemp function for this

Answer 2

Taken from here
#include <stdio.h>
int main ()
{
FILE * pFile;
pFile = fopen ("/tmp/myfile.txt","w");
if (pFile!=NULL)
{
//write
fclose (pFile);
}
return 0;
}
If /tmp/myfile.txt isn't there one will be created.

Answer 3

Here is an example:
char *tmp_file;
char buf[1000];
FILE *fp;
tmp_file = "/tmp/sometext.txt";
fp = fopen( tmp_file, "w" );
if ( fp == NULL ) {
printf("File open error! %s", tmp_file );
}
sprintf( buf, "Hello" );
fputs( buf, fp );
fclose( fp );

Answer 4

#include <stdio.h> // Defines fopen(), fclose(), fprintf(), printf(), etc.
#include <errno.h> // Defines errno
C programs generally start with the 'main()' function.
int main()
{
int rCode=0;
FILE *fp = NULL;
'fp' will be a reference to the file, used to read, write, or close the file.
char *filePath = "/tmp/thefile.txt";
'filePath' is a string that holds the path "/tmp" and the filename "thefile.txt".
The following line attempts to open the file in "write" mode, which (if successful) will cause the file "thefile.txt" to be created in the "/tmp" directory.
fp=fopen(filePath, "w");
Incidently, with the "w" (write) mode specified, it "thefile.txt" already exists in the "/tmp" directory, it will be overwritten.
The following code will print an error if the file could not be created.
if(NULL==fp)
{
rCode=errno;
fprintf(stderr, "fopen() failed. errno[%d]\n", errno);
}
After the file is created, it could be written to here:
fprintf(fp, "This is the content of the text file.\nHave a nice day!\n");
Now, the file can be closed.
if(fp)
fclose(fp);
All done.
return(rCode);
}

Answer 5

Several other people have mentioned that the correct way to do this is to use the mkstemp() function, that is because it will ensure your file has a unique name.
Here is a quick example of how to use it:
//Set file name
char filename[] = "/tmp/tmpfile-XXXXXX";
//Open the file in rw mode, X's replaced with random chars
int fd = mkstemp(filename);
//Write stuff to file...
write(fd, filename, strlen(filename));
//Close the file
close(fd);
//Do whatever else you want here, including opening and closing the file again
//Once you are done delete the temporary file
unlink(filename);
I left out error checking on purpose for clarity.