How to find development information about struct timespec

Question

I'm writing a C program using nftw() to walk a filesystem and retrieve file modification times for each file.

nftw() calls a supplied function pointer and provides a struct stat as an argument.

man stat(2) states that the time modification fields are:

struct timespec st_atim;  /* time of last access */
struct timespec st_mtim;  /* time of last modification */
struct timespec st_ctim;  /* time of last status change */

However, whilst man stat(2) provides an example of how to print the time fields, it doesn't tell me how to find information about struct timespec, nor how to query/manipulate the time modification fields.

How should I go about finding that information on my computer alone, without resorting to Google?

score 1 · Accepted Answer · answered Jan 20 '16 at 12:31

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Typically one of the man pages describes what these structures contain. If you tell us your platform I can give further details. Otherwise, open up the header /usr/include/time.h to see what struct timespec is defined as.

answered Jan 20 '16 at 12:31

fuz

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I'm running Ubuntu 15.10 64bit. – retrodev Jan 20 '16 at 12:38
I'm guessing you know to open up time.h from experience. The man page makes no reference to that header. How could I have come to that conclusion myself? – retrodev Jan 20 '16 at 12:40
@retrodev [POSIX specifies](http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/time.h.html) that this is the place where `struct timespec` is declared. – fuz Jan 20 '16 at 12:58
@retrodev You could also search for `struct timespec` in `/usr/include` to find potential declarations. – fuz Jan 20 '16 at 12:59

score 0 · Answer 2 · answered Jan 20 '16 at 12:31

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$ apropos timespec
clock_gettime        (2)  - Return the current timespec value of tp for the specified clock
$ man 2 clock_gettime

answered Jan 20 '16 at 12:31

Andrea Bergia

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On my system, the answer to the first query is “timespec: nothing appropriate.” Should I return my system? – fuz Jan 20 '16 at 12:33
No. You should use google, or if you _really_ don't want to, you can grep your include path. But why would you? – Andrea Bergia Jan 20 '16 at 12:34
I also get "timespec: nothing appropriate". – retrodev Jan 20 '16 at 12:39

terence hill · Answer 3 · 2016-01-20T12:59:41.620

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Usually, when I need information on data types or functions, if not included in the man pages, I issue a command like the following:

grep -r "timespec" /usr/include/

in the path where are the header files.

edited Jan 20 '16 at 12:59

answered Jan 20 '16 at 12:50

terence hill

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How to find development information about struct timespec

3 Answers3