fopen¶
fopen opens a file.
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fh = fopen(ssFileName, ssMode) -
fh = fopen(ssFileName, ssMode, nByteOrder)
Return Value
fh is a file handle.
Parameters
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ssFileName Path name of file.
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ssMode Type of access permitted. The character string ssMode specifies the type of access requested for the file as follows:
Value Meaning "r"Opens the file for reading. If the file does not exist or cannot be found, the fopen function returns 0. "w"Opens an empty file for writing. If the file exists, its contents are destroyed. "a"Opens the file for writing at the end of the file (appending); creates the file first if it doesn’t exist. "r+"Opens the file for both reading and writing. (The file must exist.) "w+"Opens an empty file for both reading and writing. If the given file exists, its contents are destroyed. "a+"Opens the file for reading and appending. If the given file doesn’t exist, the file will be created. In addition to the above values, the following characters can be included in ssMode to specify the translation mode for newline characters:
Value Meaning "t"Open in text (translated) mode. In text mode, carriage return-line feed combinations are translated into single line feeds on input, and linefeed characters are translated to carriage return-line feed combinations on output. CTRL+Z is interpreted as an end-of-file character on input. In files opened for reading/writing with “a+”, fopen checks for a CTRL+Z at the end of the file and removes it, if possible. Using fseek to move within a file that ends with a CTRL+Z may cause fseek to behave improperly near the end of the file. "b"Open in binary (untranslated) mode. Translations involving carriage-return and line feed characters are suppressed. If “t” or “b” is not given in mode, the default translation mode is “t”. If “t” or “b” is prefixed to the argument, the function fails and returns NULL. If
"t"or"b"is not specified the file will be opened in binary mode"b"."t"or"b"must be specified at the end of the mode parameter, for example “wt”, otherwise the function fails and returns 0.The ssMode parameter can contain an optional flag, that controls how strings are handled (see fwrite_char, fread_char and fprintf). Internally, UniPlot uses the UTF16-Format for strings. In this format a character uses 2 bytes.
Value Meaning "none"Read and write only the low order byte of a string. "ansi"Read and write ANSI (1 byte). "utf-8"Read and write UTF-8. "utf-16"Read and write UTF-16 big endian (Motorola Byte Order). "utf-16le"Read and write UTF-16 little endian (Intel Byte Order). The code ccs (coded character set) must be used as in the following example:
fopen("c:/myfile.txt", "wt, ccs=ansi");
The byte-order in the nByteOrder parameter has no effect on the coding. If the file is opened with read access and the file contains a BOM (Byte Order Mark) at the beginning of the file and
ccsis not set to none, the coding of the BOM is used and theccselement is ignored.List of BOMs:
Bytes Encoding Form EF BB BF UTF-8 FE FF UTF-16, big-endian FF FE UTF-16, little-endian 00 00 FE FF UTF-32, big-endian (not supported) FF FE 00 00 UTF-32, little-endian (not supported)
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nByteOrder nByteOrder specifies the byte order.
Value Meaning LITTLE_ENDIAN (1) Little endian byte-order (e.g. Intel Pentium). This is the default value if the function is called without this parameter BIG_ENDIAN (2) Big endian byte-order (e.g. Motorola CPU’s).
Example
Open a binary file for reading and read 100 shorts
fh = fopen("c:/test.bin", "rt");
rvValues = fread(fh, "short", 100); // reads 100 short values
fclose(fh);
Example
Open a binary file:
fh = fopen("c:/test.bin", "r");
rvValues = fread(fh, "short", 100); // reads 100 short values
fclose(fh);
Example
fh = fopen("c:/test.txt", "w");
a = rand(10,10);
fprintf(fh, "%10.2f\r\n", a);
fclose(fh);
EdCreate("c:/test.txt");
History
| Version | Description |
|---|---|
| 5.0.0 | Parameter ssMode changed. |
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