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Function getprotobynumber

Get protocol information from protocol number.

struct protoent { 
   const char *   p_name;     // official protocol name 
   const char * * p_aliases;  // alias list (will be NULL) 
   short          p_proto;    // protocol number 
   short          fill;       // reserved 
   const char *   alias;      // extended part for actual string 
}; 

struct protent * getprotobynumber(int number);

Parameters

number

Number of protocol to query (e.g. 6 for TCP, 17 for UDP, 2 for IGMP, etc).

return value

Returns a pointer to a protent structure if successful, otherwise NULL. If an error occurred, call xn_getlasterror and xn_geterror_string to return the error value. Section Error Codes further describes each error. Possible values for this function are:

Socket API

Function getprotobyname

Function getservbyname