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Archived:Creating temporary files in Open C

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Article Metadata
Tested with
Devices(s): Nokia N93
Platform(s): S60 3rd Edition
S60 3rd Edition (initial release)
Keywords: tmpnam(), tmpfile()
Created: nymanaki (02 Apr 2008)
Last edited: hamishwillee (18 Jun 2012)



Programs often need to create temporary files just for the life time of the program. In Open C tmpnam() and tempfile() functions exist to assist in this task.

  • tmpnam() generates file names that can be used for a temporary file.
  • tmpfile() creates a temporary file and opens a corresponding stream to the created file.

The tmpnam() and tmpfile() functions return a pointer to a file name on success or NULL pointer in case of an error.

Note: In order to use this code, you need to install the Open C plug-in.

This snippet can be self-signed.

MMP file

The following libraries are required:

LIBRARY libc.lib

Source file

#include <stdio.h> //fprintf, tmpnam, tmpfile, FILE
#include <sys/stat.h> //S_IWUSR
int main (void)
char *tmp_pathname = 0;
char buffer[100];
FILE *tmp_fileptr = 0;
FILE *tmp_filestream = 0;
/* create the tmp directory */
mkdir("c:\\tmp", S_IWUSR);
/* - tmpnam - */
if (!(tmp_pathname = tmpnam(NULL)))
perror("Error creating temporary filename!");
fprintf(stdout, "Temporary pathname %s\n", tmp_pathname);
if (!(tmp_fileptr = fopen(tmp_pathname, "w")))
perror("Error opening temporary file");
/* - tmpfile - */
if (!(tmp_filestream = tmpfile()))
perror("Error generating temporary stream!");
/* write to temporary file */
fprintf(tmp_filestream, "Temporary stream created by PID[%ld]", (long)getpid());
/* read from temporary file */
fgets(buffer, 100, tmp_filestream);
fprintf(stdout, "Temporary stream: %s\n", buffer);
return 0;


Two temporary files are created. The tmpfile() created file is automatically deleted by the OS when all references to the file are closed.

This page was last modified on 18 June 2012, at 06:34.
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