1 hostip.c explained 2 ================== 3 4 The main COMPILE-TIME DEFINES to keep in mind when reading the host*.c 5 source file are these: 6 7 CURLRES_IPV6 - this host has getaddrinfo() and family, and thus we use 8 that. The host may not be able to resolve IPv6, but we don't really have to 9 take that into account. Hosts that aren't IPv6-enabled have CURLRES_IPV4 10 defined. 11 12 CURLRES_ARES - is defined if libcurl is built to use c-ares for asynchronous 13 name resolves. It cannot have ENABLE_IPV6 defined at the same time, as c-ares 14 has no ipv6 support. This can be Windows or *nix. 15 16 CURLRES_THREADED - is defined if libcurl is built to run under (native) 17 Windows, and then the name resolve will be done in a new thread, and the 18 supported asynch API will be the same as for ares-builds. 19 20 If any of the two previous are defined, CURLRES_ASYNCH is defined too. If 21 libcurl is not built to use an asynchronous resolver, CURLRES_SYNCH is 22 defined. 23 24 The host*.c sources files are split up like this: 25 26 hostip.c - method-independent resolver functions and utility functions 27 hostasyn.c - functions for asynchronous name resolves 28 hostsyn.c - functions for synchronous name resolves 29 hostares.c - functions for ares-using name resolves 30 hostthre.c - functions for threaded name resolves 31 hostip4.c - ipv4-specific functions 32 hostip6.c - ipv6-specific functions 33 34 The hostip.h is the single united header file for all this. It defines the 35 CURLRES_* defines based on the config*.h and setup.h defines. 36