A POP3 Code Library by Hillstone Software

HS POP3 is a software library in C (optionally supplied with full source code) which implements the client side of Post Office Protocol Version 3 (POP3) over TCP socket layer according to RFC 1939. Among other features, the library supports user authentication, reception of basic internet headers and text, message deletion and statistics.

Features:
* POP3 Client Operation
* Server name resolution
* Supports up to 5 contexts
* Header Reception & Parsing
* Message Text Reception
* Asynchonous Operation

POP3 COMMANDS:
* USER, PASS, STAT, LIST, UIDL, RETR, DELE, QUIT

How it works:
First user application calls HS POP3 initialisation function supplying pointers to callback functions in user code for memory and timer management and for reporting POP3 events to user.

To receive email messages from any POP3 RFC1939 compliant server, the user application calls HsPop3GetMail function, specifying mail server name or IP address, login user name and password.

HS POP3 library then resolves the server name, connects to it and receives message scan list according to RFC1939 standard. Once HS POP3 has a unique message ID from the server, it reports this message ID to user application via callback function. The user application returns a specific value if it wants to receive this message. At this point HS POP3 will request necessary amount of memory for the message and will receive the complete message into the buffer. Once the message is received, the user code is notified with a callback passing a message structure, containing full message pointer, message length, start of text pointer, length of headers and separate parsed out header information: from field, date field, message id field and subject field. This process is repeated until all messages are received. HS POP3 library can also delete messages from server if this option is specified.

HS POP3 Library incorporates the necessary state machine, transparency procedures, and server response processing required to comply to a simple and robust POP3 client implementation.

Modular design makes it easy to port HS POP3 protocol module to any environment. HS POP3 internally at a lower layer interfaces to HS Sock library which provides TCP transport services. User application need not worry about Winsock - HS POP3 does all transmission, reception and event handling over socket layer.

Licensing

- Static Library Edition - Blueprint Edition