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psc.book Page 19 Monday, January 11, 1999 1:50 PM pSOSystem System Calls getsockopt #include <pna.h> long getsockopt( int s, /* int level, /* /* int optname, /* char *optval,/* int *optlen /* ) pNA+ System Calls Gets options on a socket. socket descriptor */ SOL_SOCKET, IPPROTO_IP, */ or IPPROTO_TCP */ retrieval option */ return buffer */ input/output buffer size */ Description 6 The getsockopt() system call obtains the status of options associated with the specified socket. Socket level, IP protocol level, or TCP protocol level options may be retrieved. Arguments getsockopt s Specifies the socket. level Specifies the level of the option to be queried and must be set to SOL_SOCKET for socket level operations, IPPROTO_IP for IP protocol level operations, or IPPROTO_TCP for TCP protocol level operations. optname Specifies the option to be queried, and uses a symbolic constant. The symbolic constants available for each level are provided below and in <pna.h>. optval Points to a buffer where getsockopt() stores the value for the requested option. For most options, an int is returned in the buffer pointed to by optval. A nonzero value means the option is set, and a 0 means the option is off. optlen An input-output parameter. On input, it should contain the size of the buffer pointed to by optval. On output, it contains the actual size of the value returned in the optval buffer. 6-19
