How to properly use flock()

samps005 · 05-05-2003, 09:09 PM

I am making a call to flock() and getting the error
" warning: passing arg 1 of `flock' makes integer from pointer without a cast"
when I try to compile. I am running FreeBSD and using gcc.

Code:

  flock(logfile,LOCK_EX);/*lock log file*/
  fputs("client logged in",logfile);
  flock(logfile,LOCK_UN);/*unlock log file*/

logfile is declared like this

Code:

FILE *logfile;

this is my first time every using flock(), it seems like it would be much easier than using POSIX semaphores. Does anyone know why I am getting this error? The fputs() call does not give me any errors at compile time.

thanks in advance

quzah · 05-05-2003, 09:23 PM

Read the man page for it. Then actually call it right. It uses a file descriptor. A descriptor is not the same thing as a "FILE*".

Quzah.

samps005 · 05-05-2003, 09:47 PM

sorry, I did read the man page for it, I just didn't catch that is was asking for a file descriptor.

is there anyway to get the file descriptor from the file pointer?

quzah · 05-05-2003, 10:18 PM

Quote:

Originally posted by samps005
is there anyway to get the file descriptor from the file pointer?

Do you need a file pointer? You could always use open instead. Or if you need a file pointer, I'm pretty sure there's a way to do it, but the function name escapes me at this time.

Quzah.

samps005 · 05-05-2003, 11:16 PM

yeah, I need the file pointer most of my other code needs it. Does anyone else know of a function to get a file descriptor from a file pointer? Or maybe just another really simple way to lock a file?

und3rdog · 05-06-2003, 12:22 AM

stat() might help you
-luke

05-05-2003, 09:09 PM	#1
samps005 Registered User Join Date: Oct 2002 Posts: 27	How to properly use flock() I am making a call to flock() and getting the error " warning: passing arg 1 of `flock' makes integer from pointer without a cast" when I try to compile. I am running FreeBSD and using gcc. Code: flock(logfile,LOCK_EX);/lock log file/ fputs("client logged in",logfile); flock(logfile,LOCK_UN);/unlock log file/ logfile is declared like this Code: FILE *logfile; this is my first time every using flock(), it seems like it would be much easier than using POSIX semaphores. Does anyone know why I am getting this error? The fputs() call does not give me any errors at compile time. thanks in advance
samps005 is offline

05-05-2003, 09:23 PM	#2
quzah +++ OK NO CARRIER Join Date: Oct 2001 Posts: 10,643	Read the man page for it. Then actually call it right. It uses a file descriptor. A descriptor is not the same thing as a "FILE*". Quzah. __________________ Hundreds of thousands of dipshits can't be wrong. Are you up for the suck?
quzah is offline

05-05-2003, 09:47 PM	#3
samps005 Registered User Join Date: Oct 2002 Posts: 27	sorry, I did read the man page for it, I just didn't catch that is was asking for a file descriptor. is there anyway to get the file descriptor from the file pointer?
samps005 is offline

05-05-2003, 11:16 PM	#5
samps005 Registered User Join Date: Oct 2002 Posts: 27	yeah, I need the file pointer most of my other code needs it. Does anyone else know of a function to get a file descriptor from a file pointer? Or maybe just another really simple way to lock a file?
samps005 is offline

05-06-2003, 12:22 AM	#6
und3rdog Registered User Join Date: May 2003 Posts: 15	stat() might help you -luke __________________ I'm with <----------- newb!
und3rdog is offline

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