FgetsNoNL function w/o using fgets(...)

I'm writing my own function to supplement fgets(...), with the usual objective of getting strings either from file or stdin and dropping the NL character; I almost have it working but I must be doing something horrible to the space I've allocated for my variables. It recovers all the strings I send it, and exits when the EOF is encountered, but with a 'bus error' at the end, depending on the order in which I declare my variables.

Here's the code that gives the bus error (if I declare the file pointer first, I don't get the error):

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

char* fgetsNoNL( char *line, int len, FILE *fp );

#define MAXLINE 100

int main( int argc, char *argv[] )
{
char caText[MAXLINE];
char *dum = calloc( MAXLINE, sizeof( char ) );
FILE *ifp;

if (argc == 2 ) {
ifp = fopen( argv[1], "r" );
if ( ifp == NULL ) {

fprintf( stderr, "File not found. Quitting...\n" );
exit (1);

}
}
while ( dum != NULL ) {

if ( argc == 2 && ifp != NULL )
dum = fgetsNoNL( caText, sizeof( caText ), ifp );
else
dum = fgetsNoNL( caText, sizeof( caText ), stdin );

fprintf( stderr, "%s\n", caText );

}

if ( ifp != NULL )
fclose( ifp );
}

char* fgetsNoNL( char *line, int len, FILE *fp )
{
int index = 0;
int tmp = '\0';

while( ( tmp = fgetc( fp ) ) != EOF )
{

if ( tmp == '\n' ) {
line[index] = '\0';
return line;
}
else
line[index] = tmp;

index += 1;

}

line[index] = '\0';
if ( tmp == EOF ) {

line = NULL;
return NULL;

}
return NULL;
}

Thanks in advance. I know I should free the pointer allocated for the dummy variable. It doesn't matter while the code is grumping. Thanks in advance for any tips on my use (abuse?) of memory. I'm using Apple's version of gcc in OS X 10.5 (Leopard).

The same function is very easy when using the actual fgets(...) function inside the utility function, because it does return NULL when the EOF comes up. I just want a function with the same parameters and return type as fgets(...).

Well you also need to add a test for
index < len
to make sure there is no buffer overflow.


But I have to ask why not just call fgets() anyway to do all the tricky work, then have a 1-liner to blow away the newline?

Everything is working fine now. Turns out the problem was not my buffers, but trying to close the FILE pointed to by ifp when using stdin.

Really, really dumb oversight.

I put in a test to see if argc == 2 and ifp not NULL before I try to close ifp, and initialize the FILE pointer variable to NULL at declaration.

In the function I did put a test in for exceeding the max length permitted for the string.

I went through all this to practice handling the EOF condition explicitly, learning as I go, and I was never really having problems with EOF.

Thanks for responding, salem. I hope to have more interesting matters to discuss in the future.