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copied!<p>Try this code:</p> <p>Client side:</p> <pre><code>/* Client code */ /* TODO : Modify to meet your need */ #include <stdio.h> #include <sys/types.h> #include <sys/socket.h> #include <stdlib.h> #include <errno.h> #include <string.h> #include <arpa/inet.h> #include <unistd.h> #include <netinet/in.h> #define PORT_NUMBER 5000 #define SERVER_ADDRESS "192.168.1.7" #define FILENAME "/home/toc/foo.c" int main(int argc, char **argv) { int client_socket; ssize_t len; struct sockaddr_in remote_addr; char buffer[BUFSIZ]; int file_size; FILE *received_file; int remain_data = 0; /* Zeroing remote_addr struct */ memset(&remote_addr, 0, sizeof(remote_addr)); /* Construct remote_addr struct */ remote_addr.sin_family = AF_INET; inet_pton(AF_INET, SERVER_ADDRESS, &(remote_addr.sin_addr)); remote_addr.sin_port = htons(PORT_NUMBER); /* Create client socket */ client_socket = socket(AF_INET, SOCK_STREAM, 0); if (client_socket == -1) { fprintf(stderr, "Error creating socket --> %s\n", strerror(errno)); exit(EXIT_FAILURE); } /* Connect to the server */ if (connect(client_socket, (struct sockaddr *)&remote_addr, sizeof(struct sockaddr)) == -1) { fprintf(stderr, "Error on connect --> %s\n", strerror(errno)); exit(EXIT_FAILURE); } /* Receiving file size */ recv(client_socket, buffer, BUFSIZ, 0); file_size = atoi(buffer); //fprintf(stdout, "\nFile size : %d\n", file_size); received_file = fopen(FILENAME, "w"); if (received_file == NULL) { fprintf(stderr, "Failed to open file foo --> %s\n", strerror(errno)); exit(EXIT_FAILURE); } remain_data = file_size; while (((len = recv(client_socket, buffer, BUFSIZ, 0)) > 0) && (remain_data > 0)) { fwrite(buffer, sizeof(char), len, received_file); remain_data -= len; fprintf(stdout, "Receive %d bytes and we hope :- %d bytes\n", len, remain_data); } fclose(received_file); close(client_socket); return 0; } </code></pre> <p>Server side:</p> <pre><code>/* Server code */ /* TODO : Modify to meet your need */ #include <stdio.h> #include <sys/types.h> #include <sys/socket.h> #include <stdlib.h> #include <errno.h> #include <string.h> #include <arpa/inet.h> #include <unistd.h> #include <netinet/in.h> #include <sys/stat.h> #include <fcntl.h> #include <sys/sendfile.h> #define PORT_NUMBER 5000 #define SERVER_ADDRESS "192.168.1.7" #define FILE_TO_SEND "hello.c" int main(int argc, char **argv) { int server_socket; int peer_socket; socklen_t sock_len; ssize_t len; struct sockaddr_in server_addr; struct sockaddr_in peer_addr; int fd; int sent_bytes = 0; char file_size[256]; struct stat file_stat; int offset; int remain_data; /* Create server socket */ server_socket = socket(AF_INET, SOCK_STREAM, 0); if (server_socket == -1) { fprintf(stderr, "Error creating socket --> %s", strerror(errno)); exit(EXIT_FAILURE); } /* Zeroing server_addr struct */ memset(&server_addr, 0, sizeof(server_addr)); /* Construct server_addr struct */ server_addr.sin_family = AF_INET; inet_pton(AF_INET, SERVER_ADDRESS, &(server_addr.sin_addr)); server_addr.sin_port = htons(PORT_NUMBER); /* Bind */ if ((bind(server_socket, (struct sockaddr *)&server_addr, sizeof(struct sockaddr))) == -1) { fprintf(stderr, "Error on bind --> %s", strerror(errno)); exit(EXIT_FAILURE); } /* Listening to incoming connections */ if ((listen(server_socket, 5)) == -1) { fprintf(stderr, "Error on listen --> %s", strerror(errno)); exit(EXIT_FAILURE); } fd = open(FILE_TO_SEND, O_RDONLY); if (fd == -1) { fprintf(stderr, "Error opening file --> %s", strerror(errno)); exit(EXIT_FAILURE); } /* Get file stats */ if (fstat(fd, &file_stat) < 0) { fprintf(stderr, "Error fstat --> %s", strerror(errno)); exit(EXIT_FAILURE); } fprintf(stdout, "File Size: \n%d bytes\n", file_stat.st_size); sock_len = sizeof(struct sockaddr_in); /* Accepting incoming peers */ peer_socket = accept(server_socket, (struct sockaddr *)&peer_addr, &sock_len); if (peer_socket == -1) { fprintf(stderr, "Error on accept --> %s", strerror(errno)); exit(EXIT_FAILURE); } fprintf(stdout, "Accept peer --> %s\n", inet_ntoa(peer_addr.sin_addr)); sprintf(file_size, "%d", file_stat.st_size); /* Sending file size */ len = send(peer_socket, file_size, sizeof(file_size), 0); if (len < 0) { fprintf(stderr, "Error on sending greetings --> %s", strerror(errno)); exit(EXIT_FAILURE); } fprintf(stdout, "Server sent %d bytes for the size\n", len); offset = 0; remain_data = file_stat.st_size; /* Sending file data */ while (((sent_bytes = sendfile(peer_socket, fd, &offset, BUFSIZ)) > 0) && (remain_data > 0)) { fprintf(stdout, "1. Server sent %d bytes from file's data, offset is now : %d and remaining data = %d\n", sent_bytes, offset, remain_data); remain_data -= sent_bytes; fprintf(stdout, "2. Server sent %d bytes from file's data, offset is now : %d and remaining data = %d\n", sent_bytes, offset, remain_data); } close(peer_socket); close(server_socket); return 0; } </code></pre> <p><strong>EDIT</strong> : Adding explanation from the man about the <code>offset</code></p> <p>The man page of send file said:</p> <blockquote> <p>If offset is not NULL, then it points to a variable holding the file offset from which sendfile() will start reading data from in_fd.<br> <strong>When sendfile() returns, this variable will be set to the offset of the byte following the last byte that was read</strong>.</p> </blockquote>

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