Advanced UNIX Programming

Removing Files

You delete files under UNIX using the unlink(2) system call. The function synopsis for it is as follows:

#include <unistd.h>

int unlink(const char *pathname);

A UNIX file can have more than one name linked to a copy of the file. When the last link is removed, the file itself is deleted and the disk space is returned to the file system for re-use.

The function returns -1 if it fails and leaves the error code in errno. Upon a successful return, the value 0 is returned.

The following example code shows how the pathname /tmp/12345.tmp is deleted from a C program:

if ( unlink("/tmp/12345.tmp") == -1 ) {
    fprintf(stderr,"%s: removing /tmp/12345.tmp\n",strerror(errno));
    abort();
}

All links to the same file must be released this way ...