# pcap_activate

## NAME



           pcap_activate - activate a capture handle
    


## SYNOPSIS



           **#include <pcap/pcap.h>**
    
           **int pcap_activate(pcap_t *p);**
    


## DESCRIPTION



           **pcap_activate**() is used to activate a packet capture handle to
           look at packets on the network, with the options that were set on
           the handle being in effect.
    


## RETURN VALUE



           **pcap_activate**() returns **0** on success without warnings, a non-zero
           positive value on success with warnings, and a negative value on
           error.  A non-zero return value indicates what warning or error
           condition occurred.
    
           The possible warning values are:
    
           **PCAP_WARNING_PROMISC_NOTSUP**
                  Promiscuous mode was requested, but the capture source
                  doesn't support promiscuous mode.
    
           **PCAP_WARNING_TSTAMP_TYPE_NOTSUP**
                  The time stamp type specified in a previous
                  **pcap_set_tstamp_type**(3PCAP) call isn't supported by the
                  capture source (the time stamp type is left as the
                  default),
    
           **PCAP_WARNING**
                  Another warning condition occurred; **pcap_geterr**(3PCAP) or
                  **pcap_perror**(3PCAP) may be called with _p_ as an argument to
                  fetch or display a message describing the warning
                  condition.
    
           The possible error values are:
    
           **PCAP_ERROR_ACTIVATED**
                  The handle has already been activated.
    
           **PCAP_ERROR_NO_SUCH_DEVICE**
                  The capture source specified when the handle was created
                  doesn't exist.
    
           **PCAP_ERROR_PERM_DENIED**
                  The process doesn't have permission to open the capture
                  source.
    
           **PCAP_ERROR_PROMISC_PERM_DENIED**
                  The process has permission to open the capture source but
                  doesn't have permission to put it into promiscuous mode.
    
           **PCAP_ERROR_RFMON_NOTSUP**
                  Monitor mode was specified but the capture source doesn't
                  support monitor mode.
    
           **PCAP_ERROR_IFACE_NOT_UP**
                  The capture source device is not up.
    
           **PCAP_ERROR_CAPTURE_NOTSUP**
                  Packet capture is not supported on the capture source.
    
           **PCAP_ERROR**
                  Another error occurred.  **pcap_geterr**() or **pcap_perror**() may
                  be called with _p_ as an argument to fetch or display a
                  message describing the error.
    
           If **PCAP_WARNING_PROMISC_NOTSUP** , **PCAP_ERROR_NO_SUCH_DEVICE** ,
           **PCAP_ERROR_PERM_DENIED** , or **PCAP_ERROR_CAPTURE_NOTSUP** is returned,
           **pcap_geterr**() or **pcap_perror**() may be called with _p_ as an argument
           to fetch or display an message giving additional details about the
           problem that might be useful for debugging the problem if it's
           unexpected.
    
           Additional warning and error codes may be added in the future; a
           program should check for positive, negative, and zero return
           codes, and treat all positive return codes as warnings and all
           negative return codes as errors.  **pcap_statustostr**(3PCAP) can be
           called, with a warning or error code as an argument, to fetch a
           message describing the warning or error code.
    
           If **pcap_activate**() fails, the **pcap_t *** is not closed and freed; it
           should be closed using **pcap_close**(3PCAP).
    


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