Programming

Hi,
There is a C program with
"check_log(log_loc,log_name,path)" in it.
It seems that this C program is calling a check_log function but I didn't see any function called check_log in it.
By the way, the C program itself is called 'check_log'

I am just trying to learn a litter bit about C.
Can someone explain it to me?

Thanks!

Look at the top of the source for #include directives that have "quotes".
Those files probably have a reference to the function - unless you see an extern check_log somewhere in the current file. In that case there is a separate hunk of C code that has the function.

Hi,
Thank you for helping me.
I looked and I didn't see anything in the include has it.
Here is the whole program. What do you think about the check_log line?

========================================
#include "stdio.h"
#include "stdlib.h"
#include "time.h"
#include "stddef.h"
#include <sys/types.h>
#include <unistd.h>
#include <math.h>
/*************************************************************************/
/* */
/* */
/* */
/* check_log */
/* */
/* */
/* */
/* */
/*************************************************************************/

check_log(log_loc,log_name,path)
char log_loc[30];
char log_name[30];
char path[80];
{
/*********************************************************/
/* Set up variables to be used */
/*********************************************************/

char buffer[200];

/*********************************************************/
/* Copy the logs from each machine */
/*********************************************************/

memset(buffer,0,200);
sprintf(buffer,"rcp %s%s %s%s",path,log_name,log_loc,log_name);
system(buffer);

/*********************************************************/
/* Check the logs to see if they are readable */
/*********************************************************/

memset(buffer,0,200);
strcpy(buffer,log_loc);
strcat(buffer,log_name);

if((access(buffer, F_OK)) != 0 ) {
printf("Error could not find %s.\n",buffer);
exit(0);
}
return(0);
}


=========================================

"check_log(log_loc,log_name,path)" is the function signature (or interface); it's not calling anything but it is declaring itself and its parameters to the C compiler so that some other module can invoke it. check_log() would be called by some other function external to this body of code.

check_log is part of the check_log.c file.
Is it the standard coding in front of all the C programs for other module to invoke?


Thanks for your help!

I'm not sure I understand your question. I'll see if I can simplify this a bit.

check_log.c is simply a source file that contains a function, check_log(). The "entry point" into the function is this line:

Code:

check_log(log_loc,log_name,path)

The check_log function accepts three parameters. check_log's parameter data types are declared as follows:

Code:

char log_loc[30];
char log_name[30];
char path[80];

check_log.c could contain additional functions as necessary such as purge_log(), open_log(), etc. It just so happens that it has one function and the source file name "check_log.c" suggests that you can only perform "check log" functionality.

There is no main() function in check_log.c so the function check_log() would be utilized as a utility function by other programs.

A C source file could look like this:

Code:

#include "stdio.h"
#include "stdlib.h"
...
function_a(a,b,c)
char a;
int b;
long c;
{
    ...
}

function_b()
{
   ...
}

...

main(argc, argv)
int argc;
char *argv[];
{
    function_a;
    function_b;
    ....
}

Thanks a lot!
It really helps!