_sftbuf.cpp File Reference

#include <corecrt_internal_stdio.h>
#include <corecrt_internal_ptd_propagation.h>

Include dependency graph for _sftbuf.cpp:

Go to the source code of this file.

Functions
bool	__acrt_should_use_temporary_buffer (FILE *const stream)
bool __cdecl	__acrt_stdio_begin_temporary_buffering_nolock (FILE *const public_stream)
void __cdecl	__acrt_stdio_end_temporary_buffering_nolock (bool const flag, FILE *const public_stream, __crt_cached_ptd_host &ptd)

Variables
void *	__acrt_stdout_buffer = nullptr
void *	__acrt_stderr_buffer = nullptr

Function Documentation

__acrt_should_use_temporary_buffer()

bool __acrt_should_use_temporary_buffer

(

FILE *const

stream

)

Definition at line 34 of file _sftbuf.cpp.

{
    if (stream == stderr)
    {
        return true;
    }
 
    if (stream == stdout && _isatty(_fileno(stream)))
    {
        return true;
    }
 
    return false;
}

Referenced by __acrt_stdio_begin_temporary_buffering_nolock(), __DEFINE_CPP_OVERLOAD_STANDARD_FUNC_0_0(), and common_flush_and_write_nolock().

__acrt_stdio_begin_temporary_buffering_nolock()

bool __cdecl __acrt_stdio_begin_temporary_buffering_nolock

(

FILE *const

public_stream

)

Definition at line 54 of file _sftbuf.cpp.

{
    _ASSERTE(public_stream != nullptr);
 
    __crt_stdio_stream const stream(public_stream);
 
    if (!__acrt_should_use_temporary_buffer(stream.public_stream()))
    {
        return false;
    }
 
    void** buffer;
    if (stream.public_stream() == stdout)
    {
        buffer = &__acrt_stdout_buffer;
    }
    else if (stream.public_stream() == stderr)
    {
        buffer = &__acrt_stderr_buffer;
    }
    else
    {
        return false;
    }
 
    #ifndef CRTDLL
    _cflush++; // Force library pre-termination procedure to run
    #endif
 
    // Make sure the stream is not already buffered:
    if (stream.has_any_buffer())
    {
        return false;
    }
 
    stream.set_flags(_IOWRITE | _IOBUFFER_USER | _IOBUFFER_STBUF);
    if (*buffer == nullptr)
    {
        *buffer = _malloc_crt_t(char, _INTERNAL_BUFSIZ).detach();
    }
 
    if (*buffer == nullptr)
    {
        // If we failed to allocate a buffer, use the small character buffer:
        stream->_base   = reinterpret_cast<char*>(&stream->_charbuf);
        stream->_ptr    = reinterpret_cast<char*>(&stream->_charbuf);
        stream->_cnt    = 2;
        stream->_bufsiz = 2;
        return true;
    }
 
    // Otherwise, we have a new buffer, so set it up for use:
    stream->_base   = reinterpret_cast<char*>(*buffer);
    stream->_ptr    = reinterpret_cast<char*>(*buffer);
    stream->_cnt    = _INTERNAL_BUFSIZ;
    stream->_bufsiz = _INTERNAL_BUFSIZ;
    return true;
}

Referenced by __DEFINE_CPP_OVERLOAD_STANDARD_FUNC_0_0().

__acrt_stdio_end_temporary_buffering_nolock()

void __cdecl __acrt_stdio_end_temporary_buffering_nolock	(	bool const	flag,
		FILE *const	public_stream,
		__crt_cached_ptd_host &	ptd
	)

Definition at line 120 of file _sftbuf.cpp.

{
    __crt_stdio_stream const stream(public_stream);
 
    if (!flag)
        return;
 
    if (stream.has_temporary_buffer())
    {
        // Flush the stream and tear down temporary buffering:
        __acrt_stdio_flush_nolock(stream.public_stream(), ptd);
        stream.unset_flags(_IOBUFFER_USER | _IOBUFFER_STBUF);
        stream->_bufsiz = 0;
        stream->_base   = nullptr;
        stream->_ptr    = nullptr;
    }
 
    // Note: If we expand the functionality of the _IOBUFFER_STBUF bit to
    // include other streams, we may want to clear that bit here under an
    // 'else' clause (i.e., clear bit in the case that we leave the buffer
    // permanently assigned.  Given our current use of the bit, the extra
    // code is not needed.
}

Referenced by __DEFINE_CPP_OVERLOAD_STANDARD_FUNC_0_0().

Variable Documentation

__acrt_stderr_buffer

void* __acrt_stderr_buffer = nullptr

Definition at line 27 of file _sftbuf.cpp.

Referenced by __acrt_stdio_begin_temporary_buffering_nolock(), and uninitialize_allocated_io_buffers().

__acrt_stdout_buffer

void* __acrt_stdout_buffer = nullptr

Definition at line 26 of file _sftbuf.cpp.

Referenced by __acrt_stdio_begin_temporary_buffering_nolock(), and uninitialize_allocated_io_buffers().