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1.8.1 Functions for Sending COPY Data

These functions are used to send data during COPY FROM STDIN. They will fail if called when the connection is not in COPY_IN state.

PQputCopyData

Sends data to the server during COPY_IN state.

int PQputCopyData(PGconn *conn,
                  const char *buffer,
                  int nbytes);

Transmits the COPY data in the specified buffer, of length nbytes, to the server. The result is 1 if the data was sent, zero if it was not sent because the attempt would block (this case is only possible if the connection is in nonblocking mode), or -1 if an error occurred. (Use PQerrorMessage to retrieve details if the return value is -1. If the value is zero, wait for write-ready and try again.) The application may divide the COPY data stream into buffer loads of any convenient size. Buffer-load boundaries have no semantic significance when sending. The contents of the data stream must match the data format expected by the COPY command; see COPY for details.

PQputCopyEnd

Sends end-of-data indication to the server during COPY_IN state.

int PQputCopyEnd(PGconn *conn,
                 const char *errormsg);

Ends the COPY_IN operation successfully if errormsg is NULL. If errormsg is not NULL then the COPY is forced to fail, with the string pointed to by errormsg used as the error message. (One should not assume that this exact error message will come back from the server, however, as the server might have already failed the COPY for its own reasons. Also note that the option to force failure does not work when using pre-3.0-protocol connections.) The result is 1 if the termination data was sent, zero if it was not sent because the attempt would block (this case is only possible if the connection is in nonblocking mode), or -1 if an error occurred. (Use PQerrorMessage to retrieve details if the return value is -1. If the value is zero, wait for write-ready and try again.) After successfully calling PQputCopyEnd, call PQgetResult to obtain the final result status of the COPY command. One may wait for this result to be available in the usual way. Then return to normal operation.