#include <stdio.h>
FILE *open_memstream(char **bufp,
size_t *sizep);
#include <wchar.h>
FILE *open_wmemstream(char **bufp,
size_t *sizep);
The open_memstream() and open_wmemstream() functions create a write-only,
seekable stream backed by a dynamically allocated memory buffer. The
open_memstream() function creates a byte-oriented stream, while the
open_wmemstream() function creates a wide-oriented stream.
Each stream maintains a current position and size. Initially, the position
and size are set to zero. Each write begins at the current position
and advances it the number of successfully written bytes for
open_memstream() or wide characters for open_wmemstream(). If a write
moves the current position beyond the length of the buffer, the length of
the buffer is extended and a null character is appended to the buffer.
A stream's buffer always contains a null character at the end of the
buffer that is not included in the current length.
If a stream's current position is moved beyond the current length via a
seek operation and a write is performed, the characters between the current
length and the current position are filled with null characters
before the write is performed.
After a successful call to fclose() or fflush(), the pointer referenced
by bufp will contain the start of the memory buffer and the variable referenced
by sizep will contain the smaller of the current position and the
current buffer length.
After a successful call to fflush(), the pointer referenced by bufp and
the variable referenced by sizep are only valid until the next write
operation or a call to fclose().
Once a stream is closed, the allocated buffer referenced by bufp should
be released via a call to free() when it is no longer needed.
Upon successful completion, open_memstream() and open_wmemstream() return
a FILE pointer. Otherwise, NULL is returned and the global variable
errno is set to indicate the error.
- EINVAL
-
The bufp or sizep argument was NULL.
- ENOMEM
-
Memory for the stream or buffer could not be allocated.
IEEE Std 1003.1-2008 'POSIX.1'
MT-Safe.
None.
PTC MKS Toolkit for Professional Developers
PTC MKS Toolkit for Professional Developers 64-Bit Edition
PTC MKS Toolkit for Enterprise Developers
PTC MKS Toolkit for Enterprise Developers 64-Bit Edition
- Functions:
- fclose(), fflush(), fopen(), free(), fseek()
PTC MKS Toolkit 10.4 Documentation Build 39.