=pod =head1 NAME BIO_s_file, BIO_new_file, BIO_new_fp, BIO_set_fp, BIO_get_fp, BIO_read_filename, BIO_write_filename, BIO_append_filename, BIO_rw_filename - FILE bio =head1 SYNOPSIS #include const BIO_METHOD * BIO_s_file(void); BIO *BIO_new_file(const char *filename, const char *mode); BIO *BIO_new_fp(FILE *stream, int flags); BIO_set_fp(BIO *b,FILE *fp, int flags); BIO_get_fp(BIO *b,FILE **fpp); int BIO_read_filename(BIO *b, char *name) int BIO_write_filename(BIO *b, char *name) int BIO_append_filename(BIO *b, char *name) int BIO_rw_filename(BIO *b, char *name) =head1 DESCRIPTION BIO_s_file() returns the BIO file method. As its name implies it is a wrapper round the stdio FILE structure and it is a source/sink BIO. Calls to BIO_read() and BIO_write() read and write data to the underlying stream. BIO_gets() and BIO_puts() are supported on file BIOs. BIO_flush() on a file BIO calls the fflush() function on the wrapped stream. BIO_reset() attempts to change the file pointer to the start of file using fseek(stream, 0, 0). BIO_seek() sets the file pointer to position B from start of file using fseek(stream, ofs, 0). BIO_eof() calls feof(). Setting the BIO_CLOSE flag calls fclose() on the stream when the BIO is freed. BIO_new_file() creates a new file BIO with mode B the meaning of B is the same as the stdio function fopen(). The BIO_CLOSE flag is set on the returned BIO. BIO_new_fp() creates a file BIO wrapping B. Flags can be: BIO_CLOSE, BIO_NOCLOSE (the close flag) BIO_FP_TEXT (sets the underlying stream to text mode, default is binary: this only has any effect under Win32). BIO_set_fp() set the fp of a file BIO to B. B has the same meaning as in BIO_new_fp(), it is a macro. BIO_get_fp() retrieves the fp of a file BIO, it is a macro. BIO_seek() is a macro that sets the position pointer to B bytes from the start of file. BIO_tell() returns the value of the position pointer. BIO_read_filename(), BIO_write_filename(), BIO_append_filename() and BIO_rw_filename() set the file BIO B to use file B for reading, writing, append or read write respectively. =head1 NOTES When wrapping stdout, stdin or stderr the underlying stream should not normally be closed so the BIO_NOCLOSE flag should be set. Because the file BIO calls the underlying stdio functions any quirks in stdio behaviour will be mirrored by the corresponding BIO. On Windows BIO_new_files reserves for the filename argument to be UTF-8 encoded. In other words if you have to make it work in multi- lingual environment, encode file names in UTF-8. =head1 EXAMPLES File BIO "hello world": BIO *bio_out; bio_out = BIO_new_fp(stdout, BIO_NOCLOSE); BIO_printf(bio_out, "Hello World\n"); Alternative technique: BIO *bio_out; bio_out = BIO_new(BIO_s_file()); if(bio_out == NULL) /* Error ... */ if(!BIO_set_fp(bio_out, stdout, BIO_NOCLOSE)) /* Error ... */ BIO_printf(bio_out, "Hello World\n"); Write to a file: BIO *out; out = BIO_new_file("filename.txt", "w"); if(!out) /* Error occurred */ BIO_printf(out, "Hello World\n"); BIO_free(out); Alternative technique: BIO *out; out = BIO_new(BIO_s_file()); if(out == NULL) /* Error ... */ if(!BIO_write_filename(out, "filename.txt")) /* Error ... */ BIO_printf(out, "Hello World\n"); BIO_free(out); =head1 RETURN VALUES BIO_s_file() returns the file BIO method. BIO_new_file() and BIO_new_fp() return a file BIO or NULL if an error occurred. BIO_set_fp() and BIO_get_fp() return 1 for success or 0 for failure (although the current implementation never return 0). BIO_seek() returns the same value as the underlying fseek() function: 0 for success or -1 for failure. BIO_tell() returns the current file position. BIO_read_filename(), BIO_write_filename(), BIO_append_filename() and BIO_rw_filename() return 1 for success or 0 for failure. =head1 BUGS BIO_reset() and BIO_seek() are implemented using fseek() on the underlying stream. The return value for fseek() is 0 for success or -1 if an error occurred this differs from other types of BIO which will typically return 1 for success and a non positive value if an error occurred. =head1 SEE ALSO L, L, L, L, L, L, L, L, L, L, L =cut