#include <openssl/bio.h> 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)
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 ofs 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 mode the meaning of mode 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 stream. 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 fp. flags 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 offset bytes from the start of file.
BIO_tell() returns the value of the position pointer.
Because the file BIO calls the underlying stdio functions any quirks in stdio behaviour will be mirrored by the corresponding BIO.
BIO *bio_out; bio_out = BIO_new_fp(stdout, BIO_NOCLOSE); BIO_printf(bio_out, "Hello World\n");
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);
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);
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.