BIOsfile(3) OpenSSL BIOsfile(3)

NAME
       BIOsfile, BIOnewfile, BIOnewfp, BIOsetfp, BIOgetfp,
       BIOreadfilename, BIOwritefilename, BIOappendfilename,
       BIOrwfilename - FILE bio

SYNOPSIS
        #include 

        BIOMETHOD *   BIOsfile(void);
        BIO *BIOnewfile(const char *filename, const char *mode);
        BIO *BIOnewfp(FILE *stream, int flags);

        BIOsetfp(BIO *b,FILE *fp, int flags);
        BIOgetfp(BIO *b,FILE **fpp);

        int BIOreadfilename(BIO *b, char *name)
        int BIOwritefilename(BIO *b, char *name)
        int BIOappendfilename(BIO *b, char *name)
        int BIOrwfilename(BIO *b, char *name)

DESCRIPTION
       BIOsfile() 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 BIOread() and BIOwrite() read and write data to the
       underlying stream. BIOgets() and BIOputs() are supported on file
       BIOs.

       BIOflush() on a file BIO calls the fflush() function on the wrapped
       stream.

       BIOreset() attempts to change the file pointer to the start of file
       using fseek(stream, 0, 0).

       BIOseek() sets the file pointer to position ooffss from start of file
       using fseek(stream, ofs, 0).

       BIOeof() calls feof().

       Setting the BIOCLOSE flag calls fclose() on the stream when the BIO is
       freed.

       BIOnewfile() creates a new file BIO with mode mmooddee the meaning of
       mmooddee is the same as the stdio function fopen(). The BIOCLOSE flag is
       set on the returned BIO.

       BIOnewfp() creates a file BIO wrapping ssttrreeaamm. Flags can be:
       BIOCLOSE, BIONOCLOSE (the close flag) BIOFPTEXT (sets the
       underlying stream to text mode, default is binary: this only has any
       effect under Win32).

       BIOsetfp() set the fp of a file BIO to ffpp. ffllaaggss has the same meaning
       as in BIOnewfp(), it is a macro.

       BIOgetfp() retrieves the fp of a file BIO, it is a macro.

       BIOseek() is a macro that sets the position pointer to ooffffsseett bytes
       from the start of file.

       BIOtell() returns the value of the position pointer.

       BIOreadfilename(), BIOwritefilename(), BIOappendfilename() and
       BIOrwfilename() set the file BIO bb to use file nnaammee for reading,
       writing, append or read write respectively.

NNOOTTEESS
       When wrapping stdout, stdin or stderr the underlying stream should not
       normally be closed so the BIONOCLOSE 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.

EEXXAAMMPPLLEESS
       File BIO "hello world":

        BIO *bioout;
        bioout = BIOnewfp(stdout, BIONOCLOSE);
        BIOprintf(bioout, "Hello World\n");

       Alternative technique:

        BIO *bioout;
        bioout = BIOnew(BIOsfile());
        if(bioout == NULL) /* Error ... */
        if(!BIOsetfp(bioout, stdout, BIONOCLOSE)) /* Error ... */
        BIOprintf(bioout, "Hello World\n");

       Write to a file:

        BIO *out;
        out = BIOnewfile("filename.txt", "w");
        if(!out) /* Error occurred */
        BIOprintf(out, "Hello World\n");
        BIOfree(out);

       Alternative technique:

        BIO *out;
        out = BIOnew(BIOsfile());
        if(out == NULL) /* Error ... */
        if(!BIOwritefilename(out, "filename.txt")) /* Error ... */
        BIOprintf(out, "Hello World\n");
        BIOfree(out);

RETURN VALUES
       BIOsfile() returns the file BIO method.

       BIOnewfile() and BIOnewfp() return a file BIO or NULL if an error
       occurred.

       BIOsetfp() and BIOgetfp() return 1 for success or 0 for failure
       (although the current implementation never return 0).

       BIOseek() returns the same value as the underlying fseek() function: 0
       for success or -1 for failure.

       BIOtell() returns the current file position.

       BIOreadfilename(), BIOwritefilename(),  BIOappendfilename() and
       BIOrwfilename() return 1 for success or 0 for failure.

BUGS
       BIOreset() and BIOseek() 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.

SEE ALSO
       BIOseek(3), BIOtell(3), BIOreset(3), BIOflush(3), BIOread(3),
       BIOwrite(3), BIOputs(3), BIOgets(3), BIOprintf(3),
       BIOsetclose(3), BIOgetclose(3)



0.9.7l                            2000-09-18                     BIOsfile(3)