diff options
Diffstat (limited to 'contrib/libpcap/pcap-tstamp.manmisc.in')
| -rw-r--r-- | contrib/libpcap/pcap-tstamp.manmisc.in | 51 |
1 files changed, 47 insertions, 4 deletions
diff --git a/contrib/libpcap/pcap-tstamp.manmisc.in b/contrib/libpcap/pcap-tstamp.manmisc.in index f86f83324a57..2e1ef61d1f46 100644 --- a/contrib/libpcap/pcap-tstamp.manmisc.in +++ b/contrib/libpcap/pcap-tstamp.manmisc.in @@ -19,7 +19,7 @@ .\" WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF .\" MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. .\" -.TH PCAP-TSTAMP @MAN_MISC_INFO@ "21 December 2013" +.TH PCAP-TSTAMP @MAN_MISC_INFO@ "8 March 2015" .SH NAME pcap-tstamp \- packet time stamps in libpcap .SH DESCRIPTION @@ -104,12 +104,12 @@ precision of this time stamp is unspecified; it might or might not be synchronized with the host operating system's clock. .TP 5 .BR PCAP_TSTAMP_HOST_LOWPREC " - " host_lowprec -Time stamp provided by the host on which the capture is being done. +Time stamp provided by the host on which the capture is being done. This is a low-precision time stamp, synchronized with the host operating system's clock. .TP 5 .BR PCAP_TSTAMP_HOST_HIPREC " - " host_hiprec -Time stamp provided by the host on which the capture is being done. +Time stamp provided by the host on which the capture is being done. This is a high-precision time stamp; it might or might not be synchronized with the host operating system's clock. It might be more expensive to fetch than @@ -125,8 +125,51 @@ Time stamp provided by the network adapter on which the capture is being done. This is a high-precision time stamp; it is not synchronized with the host operating system's clock. .RE +.LP +By default, when performing a live capture or reading from a savefile, +time stamps are supplied as seconds since January 1, 1970, 00:00:00 UTC, +and microseconds since that seconds value, even if higher-resolution +time stamps are available from the capture device or in the savefile. +If, when reading a savefile, the time stamps in the file have a higher +resolution than one microsecond, the additional digits of resolution are +discarded. +.LP +The +.BR pcap_set_tstamp_precision (3PCAP) +routine can be used after a +.B pcap_create() +call and after a +.B pcap_activate() +call to specify the resolution of the time stamps to get for the device. +If the hardware or software cannot supply a higher-resolution time +stamp, the +.B pcap_set_tstamp_precision() +call will fail, and the time stamps supplied after the +.B pcap_activate() +call will have microsecond resolution. +.LP +When opening a savefile, the +.BR pcap_open_offline_with_tstamp_precision (3PCAP) +and +.BR pcap_fopen_offline_with_tstamp_precision (3PCAP) +routines can be used to specify the resolution of time stamps to be read +from the file; if the time stamps in the file have a lower resolution, +the fraction-of-a-second portion of the time stamps will be scaled to +the specified resolution. +.LP +The +.BR pcap_get_tstamp_precision (3PCAP) +routine returns the resolution of time stamps that will be supplied; +when capturing packets, this does not reflect the actual precision of +the time stamp supplied by the hardware or operating system and, when +reading a savefile, this does not indicate the actual precision of time +stamps in the file. .SH SEE ALSO pcap_set_tstamp_type(3PCAP), pcap_list_tstamp_types(3PCAP), pcap_tstamp_type_val_to_name(3PCAP), -pcap_tstamp_type_name_to_val(3PCAP) +pcap_tstamp_type_name_to_val(3PCAP), +pcap_set_tstamp_precision(3PCAP), +pcap_open_offline_with_tstamp_precision(3PCAP), +pcap_fopen_offline_with_tstamp_precision(3PCAP), +pcap_get_tstamp_precision(3PCAP) |