C language: write to file without buffering

Question

I have opened a file for writing some data to a file, but it keeps buffering and won't write anything to the file until the program ends. How can I skip the buffering process and write directly to the file.

My code:

fprintf (fp, "# Step: %d  %f\n", ntot, eDiff);
for(i=0; i<nType; i++)  
    fprintf (fp, "%s  %f %f\n",param[i].cTypes, param[i].eps, param[i].sigma);
fprintf(fp, "#  ============\n");

It may be the OS that is buffering in some weird way, if there is any buffering at all. There is something that may help -> http://stackoverflow.com/questions/1716296/why-does-printf-not-flush-after-the-call-unless-a-newline-is-in-the-format-strin — Etherealone, May 15 '13 at 21:38
You're missing the fopen, fsync, and fclose calls. You're even missing main(). How do you expect us to help you? — CAFxX, May 15 '13 at 21:39

score 4 · Accepted Answer · answered May 15 '13 at 21:39

4

Use the fflush() function on the stream:

fflush( fp );

answered May 15 '13 at 21:39

svk

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Or you can use `setbuf(fp, NULL);` – Nandakumar Edamana Mar 08 '15 at 06:35

C language: write to file without buffering

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