sending an email from a C/C++ program in linux
You could invoke your local MTA directly using popen() and feed it RFC822-compliant text.
#include <stdio.h>#include <string.h>#include <errno.h>int sendmail(const char *to, const char *from, const char *subject, const char *message){ int retval = -1; FILE *mailpipe = popen("/usr/lib/sendmail -t", "w"); if (mailpipe != NULL) { fprintf(mailpipe, "To: %s\n", to); fprintf(mailpipe, "From: %s\n", from); fprintf(mailpipe, "Subject: %s\n\n", subject); fwrite(message, 1, strlen(message), mailpipe); fwrite(".\n", 1, 2, mailpipe); pclose(mailpipe); retval = 0; } else { perror("Failed to invoke sendmail"); } return retval;}main(int argc, char** argv){ int i; printf("argc = %d\n", argc); for (i = 0; i < argc; i++) printf("argv[%d] = \"%s\"\n", i, argv[i]); sendmail(argv[1], argv[2], argv[3], argv[4]);}
libESMTP seems to be what you are looking for. It's very well documented and also seems to be under active development (last Release Candidate is from mid-January 2012). It also supports SSL and various authentication protocols.
There are example applications in the source package.