Civetweb API Reference
mg_read( conn, buf, len );
Parameters
| Parameter | Type | Description |
|---|---|---|
conn |
struct mg_connection * |
A pointer referencing the connection |
buf |
void * |
A pointer to the location where the received data can be stored |
len |
size_t |
The maximum number of bytes to be stored in the buffer |
Return Value
| Type | Description |
|---|---|
int |
The number of read bytes, or a status indication |
Description
The function mg_read() receives data over an existing connection. The data is handled as binary and is stored in a buffer whose address has been provided as a parameter. The function returns the number of read bytes when successful, the value 0 when the connection has been closed by peer and a negative value when no more data could be read from the connection.
Example
#define RECV_BUF_SIZE 1 << 20
size_t read_data(struct mg_connection* conn,
uint8_t* buff,
size_t buff_len) {
size_t read_len = 0;
while (read_len < buff_len) {
size_t sz_to_read = std::min<size_t>(RECV_BUF_SIZE, buff_len - read_len);
int this_read = mg_read(conn, buff + read_len, sz_to_read);
if (this_read < 0) {
std::cerr << "[error] Failed to read data" << std::endl;
break;
} else {
read_len += size_t(this_read);
if (this_read > 0) {
std::cout << "[debug] Received " << this_read << " more bytes" << std::endl;
}
}
}
return read_len;
}