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POOpening a file from within a function
 

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    <p>I'm working on a piece of homework and I want to send a FILE * into a function as an argument since I have to open 3 files in an identical manner with some "flavor text". I got it to work fine like this: </p> <pre><code>enum {IN, STAT, REPRINT} FNAMES; #define FNAME_MAX 256 int main(void) { FILE *in, *stat, *reprint; char fnames[3][FNAME_MAX]; // store actual file names input by user char format[11]; // format identifier used in scanf for file names in = stat = reprint = NULL; // TODO: Check necessity buildFormat(format); // this translates FNAME_MAX into the string "%256s[^\n]" // TODO: Find out why this cannot be put into a function! // open the input file while (in == NULL) { // get input file name getFileName(format, fnames[IN]); // simply prompts for a file name/path // open the input file for reading in = fopen(fnames[IN], "r"); // make sure it opened if (in == NULL) printf("%s did not open, please check spelling/path.\n\n", fnames[IN]); else printf("%s was opened successfully.\n\n", fnames[IN]); } return 0; } </code></pre> <p>What will not work is this:</p> <pre><code>void openFile(FILE *in, char *format, char *fname, char *openFor) { // TODO: Find out why this cannot be put into a function! // open the input file while (in == NULL) { // get input file name getFileName(format, fname); // simply prompts for a file name/path // open the input file for reading in = fopen(fname, openFor); // make sure it opened if (in == NULL) printf("%s did not open, please check spelling/path.\n\n", fname); else printf("%s was opened successfully.\n\n", fname); } } </code></pre> <p>if I put file reading operations in the function it works fine, but if I go back to main and try to use the file pointer I sent in it doesn't work.</p>
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    1. USJared Beekman
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    1. COhttp://c-faq.com/ptrs/passptrinit.html
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    2. COpointer to a pointer, do you speak it? and why are you *returning a value* from this function you declare as returning void?
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      1. UStbert
 

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