=pod =head1 NAME BIO_s_fd, BIO_set_fd, BIO_get_fd, BIO_new_fd - file descriptor BIO =head1 SYNOPSIS #include BIO_METHOD * BIO_s_fd(void); #define BIO_set_fd(b,fd,c) BIO_int_ctrl(b,BIO_C_SET_FD,c,fd) #define BIO_get_fd(b,c) BIO_ctrl(b,BIO_C_GET_FD,0,(char *)c) BIO *BIO_new_fd(int fd, int close_flag); =head1 DESCRIPTION BIO_s_fd() returns the file descriptor BIO method. This is a wrapper round the platforms file descriptor routines such as read() and write(). BIO_read() and BIO_write() read or write the underlying descriptor. BIO_puts() is supported but BIO_gets() is not. If the close flag is set then then close() is called on the underlying file descriptor when the BIO is freed. BIO_reset() attempts to change the file pointer to the start of file using lseek(fd, 0, 0). BIO_set_fd() sets the file descriptor of BIO B to B and the close flag to B. BIO_get_fd() places the file descriptor in B if it is not NULL, it also returns the file descriptor. If B is not NULL it should be of type (int *). BIO_new_fd() returns a file descriptor BIO using B and B. =head1 NOTES The behavior of BIO_read() and BIO_write() depends on the behavior of the platforms read() and write() calls on the descriptor. If the underlying file descriptor is in a non blocking mode then the BIO will behave in the manner described in the L and L manual pages. File descriptor BIOs should not be used for socket I/O. Use socket BIOs instead. =head1 RETURN VALUES BIO_s_fd() returns the file descriptor BIO method. BIO_reset() returns zero for success and -1 if an error occurred. BIO_seek() and BIO_tell() return the current file position or -1 is an error occurred. These values reflect the underlying lseek() behavior. BIO_set_fd() always returns 1. BIO_get_fd() returns the file descriptor or -1 if the BIO has not been initialized. BIO_new_fd() returns the newly allocated BIO or NULL is an error occurred. =head1 EXAMPLE This is a file descriptor BIO version of "Hello World": BIO *out; out = BIO_new_fd(fileno(stdout), BIO_NOCLOSE); BIO_printf(out, "Hello World\n"); BIO_free(out); =head1 SEE ALSO L, L, TBA