reassigning FILE pointers & fprintf

I want a way to selectively turn on & off file inputs at compile time without commenting out large portions of code. I thought I could do this:

Code:

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FILE* fileout;

if(NoWrite)  //NoWrite = 1 means no output
fileout = NULL;
else if((fileout=fopen("put.out","w"))==NULL)
printf("Could not open output file!\n");

fprintf(fileout,"writing to output file\n");
//many more of these, and in other places

fclose(fileout);

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but I get access violations, presumably because you can't pass fprintf a NULL pointer. So what else can I do to disable opening & printing of the output file? The program I'm writing needs to operate off a CD without writing any outputs.

Thanks!

Code:

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fileout = stdout;
.
.
.
if(NoWrite ! = 1)
  fclose(fileout);

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Cshot, unfortunately I can't write it all to stdout.

Quote:

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Originally posted by Salem
Ideally, all your logging functions should go through a separate function, so you can apply your 'NoWrite' test in a single place

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I do. I just didn't feel like posting that much detail of our code.

So there's a NULL pointer and a NUL device? No mention of NUL in MSVC++'s documentation.

You could use #define to control how sections of code are used at compile time. For example:

Code:

---

#define MY_DEBUG_FLAG


FILE *fp;
#ifdef MY_DEBUG_FLAG
    fp=fopen(....);
    fprintf(fp, "my message");
    fclose(fp);
#endif

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