Writing to A NON-Existing File in "C"
William E. Davidsen Jr
davidsen at steinmetz.steinmetz.ge.com
Thu Apr 7 00:23:31 AEST 1988
In article <9654 at jplgodo.UUCP> deutsch at jplgodo.UUCP (Michael Deutsch ) writes:
|
| I have a "C" program that records the program
| results into a file, provided that file already
| exists. In case the file DOES NOT exist I want
| the program to function identically but the results
| should be flushed down the tube, i.e. nowhere, i.e.
| written to a non-existing file?
First problem is to open the file if it exists, by
fp = fopen(MYFILE, "r+"); /* open, no create */
outflag = fp != NULL; /* set a flag */
if (outflag) fseek(fp, 0L, 2); /* rewind if open ok */
You can then print to the file using a macro, such as:
#define cprintf if (outflag) fprintf
.
.
cprintf(fp, "format", data);
--
bill davidsen (wedu at ge-crd.arpa)
{uunet | philabs | seismo}!steinmetz!crdos1!davidsen
"Stupidity, like virtue, is its own reward" -me
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