CStdioFile::ReadString
Reads text data into a buffer, up to a limit of nMax–1 characters, from the file associated with the CStdioFile object.
virtual LPTSTR ReadString(
LPTSTR lpsz,
UINT nMax
);
virtual BOOL ReadString(
CString& rString
);
Parameters
lpsz
Specifies a pointer to a user-supplied buffer that will receive a null-terminated string.nMax
Specifies the maximum number of characters to read, not including the terminating null character.rString
A reference to a CString object that contains the read string when the function returns.
Return Value
If you use the version that returns a LPTSTR, the method returns either a pointer to the buffer that contains the text data or NULL if end-of-file was reached without reading any data.
If you use the version that returns a BOOL, the method returns FALSE if end-of-file was reached without reading any data; otherwise, the method returns TRUE.
Remarks
Reading is stopped by the first newline character. If the method reads fewer than nMax–1 characters, it appends a newline character to the buffered string. The method appends a NUL character (\0) regardless of the number of read characters.
CFile::Read is also available for text-mode input, but it does not terminate on a carriage return–linefeed pair.
This method throws a CFileException* if it is unable to read the string from the file or if you specify NULL for the nMax parameter.
This method throws a CInvalidArgException* if you specify NULL for the lpsz parameter.
If you specify a negative value for the nMax parameter, the calling application exits unexpectedly.
Note
The version of this method that returns a BOOL removes the \n if present; the version that returns a LPTSTR does not.
Example
CStdioFile f(stdin);
TCHAR buf[100];
f.ReadString(buf, 99);
Requirements
Header: afx.h
See Also
Reference
Other Resources
Change History
Date |
History |
Reason |
|---|---|---|
July 2009 |
Added exception descriptions and cleaned up topic. |
Information enhancement. |