Thread: strptime Warning

I'm trying to use strptime to convert a string to a time structure, but I'm getting this warning from gcc:

Code:

main.c:198: warning: comparison between pointer and integer

This is the line that is causing the problem:

Code:

if (strptime (timeString, "%Y-%m-%d", &dStart) == NULL)

Which should work according to information that I've found online, and the strptime man page. Anyone have any idea what's wrong?

Does your program link? strptime is not a standard function, so you will need to (a) make sure it exists on your machine (b) with the signature you think it has (c) and with the prototype visible from the headers.

Originally Posted by bithub

Are you including time.h?
If so, can you show how timeString and dStart are declared?

I am including time.h
Here are my declarations:

Code:

struct tm dStart, dEnd, cDate;

char *timeString;

I have confirmed that timeString contains "2003-09-31"

Originally Posted by tabstop

Does your program link? strptime is not a standard function, so you will need to (a) make sure it exists on your machine (b) with the signature you think it has (c) and with the prototype visible from the headers.

It appears to be linking fine. I checked for strptime in time.h and it is in there with the same declaration.

Originally Posted by bithub

It should work if you put:
#define __USE_XOPEN
on the line right before you include time.h.

So it does, thanks.

As an aside, I had already tried this using "#define _XOPEN_SOURCE" which was specified in the man page on my system, but it didn't work like yours did. Can you explain this at all? I'm not familiar with requiring special defines before includes, or why it doesn't work if I try to define it on a different line (which I just checked).

Originally Posted by itCbitC

What OS and platform are you on?
Post the code here if it ain't too big.

If on Linux check out the "Notes" section of the strptime() manpage which explains why that directive is needed.

I'm on Ubuntu 9.04. The code is pretty big, but the previous suggestion worked.